I have had this a month now, so feel as though I have experienced enough pros and cons to write a thorough review. In my opinion, this is one of the best fitness trackers available on the market right now, having tested three of them--Garmin Vivofit, fitbit Charge HR, and this one. The Charge HR was my ideal choice, with supposed continual heart rate monitoring for the most accurate calorie burn, but that turned out to be a joke (read the reviews on that one to see how unimpressive the HR function is). The Vivofit had an HR chest strap, like the Polar, which worked fine, but the band itself lacked features such as auto-sleep and backlighting, which made it a pain to use overnight. It also looked a little 1998 to me. Which leads me into my "cons" list for Polar A300... (I realize I am reviewing the Polar a300 that is sold WITHOUT chest strap as I already owned the H7 strap. Understand that you must have this accessory to utilize the HR function.)

Cons
Clunky on wrist. It's BIG and very activewear/fitness-inspired, which is all well and good except for when you wear business attire to the office every day--looks out of place and it's glaringly obvious since it's so large, but must be worn all day to track activity.

The Polar watch, too, looks a little dated--I have an original Polar HR watch from around 2003 and they really haven't changed that much display-wise--this is not an LCD display but a pixelated digital display. Also would like to have the caller ID feature from other brands of trackers.

I am not entirely sure the pedometer is as precise as the fitbit (I hated the charge HR for everything else but counting steps--seemed the most accurate to me); when I wore the Charge HR I found myself making extra chores to get in my 10,000 steps, whereas with the Polar I hit my goal every single day without really trying. I think it may pick up arm movement as "walking" sometimes.

You must manually open the app and manually sync the watch to your phone to update results. I would think there would have been an auto-sync function, but I am guessing that's a trade-off for extended battery life. Not a huge deal, but sort of annoying.

Pros
I find Polar to have the most accurate HR tracking on the market today across any fitness device. I have an arrhythmia, so I need to track HR during workouts in case I begin having an extremely rapid HR, in which case I have to decrease intensity immediately. (That sounds like you'd just know, but in the middle of a tough workout, sometimes you just FEEL like your heart is beating crazy fast when it's not. Or at least I do.) I also have a naturally faster heart beat from this problem, so my HR limits are different than other people's, so I particularly like the ability to set your own HR limits and have alarms go off if you are out of your zone. It's accurate even during the most intense routines, and I never have issues with syncing or HR "dropping out" as some others have said. Be sure you wet the contact area of the chest strap before putting it on. I usually pour some water on it, but even spit works in a pinch. I've never had to use the electrode gel.

Long battery life and ease of charging. I know, I just complained about the display and sync features above, but I think that's probably part of the reason the battery lasts so long on the Polar. It's nice to be able to go a week in between charges, and the charging typically takes about an hour for me. I did not realize when I purchased that it needs a computer for charging, though, so beware--it just has a USB port on one end, so you could probably plug it into a phone AC adapter, but I don't know enough about electrical currents/voltage to know if that's a good idea or not. There was one instance where I was away overnight and low on battery and worried because I didn't have my laptop with me, but the battery held on long enough for me to return home and charge the next day.

App syncing with Myfitnesspal. It's so nice to be able to have your exercise directly import into calorie-tracking programs. I hope to soon see more platforms accepting data from the Polar Flow app, particularly Sparkpeople, but for now am content with myfitnesspal.com.

Price. The A300 is pretty affordable, especially considering some of the other HR trackers on the market today. And you can switch the band out, which I guess is cool, but I haven't bought any of the other bands myself because they're all pretty brightly-colored and I'm trying to minimize the look as much as possible.

There are definitely things I wish I could change to truly have the perfect activity tracker, but all in all, I am pleased with the Polar and will stick with the A300 for the predictable future.

I've had this watch/fitness tracker for 5 months now and have been wearing it daily. Here are some pros and cons:

Cons:
* Wrist strap is too "rubbery". I wish it was constructed of a stiffer plastic. The rubbery texture can grab on sleeves when you're putting on long sleeve shirts. My watch band also has a small rip (1/4") in the rubber near the watch face. This rip hasn't gotten larger, but I'm sure I'll need to replace the band eventually. The band can also collect dust and debris, but a quick rinse in the sink cleans it off.
* Since the latest firmware update (which includes smart notifications), the watch hasn't synced as well with the android Polar Flow app. It used to sync almost flawlessly (sometimes I would have to run the sync twice), but since this firmware update, the watch sometimes doesn't connect to my phone at all when trying to sync. Resetting the pairing connection between the watch and phone helped, but it's still not as good as before.
* Heart rate accuracy can fluctuate if you don't have a good connection between your skin and the chest strap. The first few months of use was strictly indoors in spin class and the accuracy was great. But since I've started biking outdoors the heart rate is less reliable. It's usually fine, the problems typically occur when I'm going downhill and my sweat has dried up. I just bought some heart rate monitor gel (search for 'electrode gel' here on Amazon), which seems to help, but if you're not sweating much or not using gel, the chest strap doesn't work 100%. I even tried a new battery in the chest strap, but that didn't help, so I'm certain it's the quality of the contact between the strap and your skin.

Pros:
* Smart notifications are cool! The latest firmware update includes the new Smart Notifications feature. I use the device settings in the android app to block notifications from apps I don't care about and only get notifications on the watch for things like emails and text messages. This is a great feature and really makes wearing the watch every day more worthwhile.
* Recording workout sessions is very easy. Press a button, select an activity profile (or just use the same profile as last time), then press 'start'.
* The H7 chest strap can pair using bluetooth with my Strava app. I don't always use this feature since the extra bluetooth usage drains my phone battery more quickly, but it's nice to know it works in case I want to leave the watch at home and just use Strava.
* The Polar flow app on android syncs to Google Fit. If you use Fit for tracking your activity, you can have the data from your A300 included in Fit.
* USB syncing on my Mac works well. Considering that the wireless sync to my phone doesn't always work, I'm glad I can easily plug the watch (USB plug is built in) into my computer's USB port to charge and sync.
* Battery life is acceptable. I can easily get a week or two of use between charges of the watch. My wife has a fitbit charge HR and she has to charge it every couple days. The watch charges when I plug it into my computer to sync and I usually do that before the battery is too low anyway.

Final thought: I don't really use the activity tracking features much. It's a nice to have feature, but the heart rate monitor (chest strap required) is the most important feature for me. If it wasn't for the new smart notifications, I might not be wearing the watch daily. If I was trying to lose weight, maybe I'd pay more attention to my activity levels, but I'm active enough that I don't worry about that much.

I purchased no less than five other activity trackers before I found this one: the Garmin Vivofit 2, the Garmin Vivosmart HR, Fitbit Charge HR, Fitbit Blaze, and the Mio Fuse. The Polar A300 was perfect for my lifestyle; I workout 6 days per week for at least an hour per day. My workouts include at least 3-5 days of heavy weight training, Hiit, bootcamp or circuit style workouts, yoga, and spin class. The Polar A300 provides an comprehensive tracking system. I'm no longer tracking my workouts with one app, then going to another to see my steps, sleep and daily activity. The Polar does it all! The Polar A300 is a very functional fitness tracker. It has all of the features of the Garmin and the Fitbit, but it simply works better. If your sole activity for exercise is running, then any of these will probably work for you. If you do any other type of exercise, the Polar is the way to go.
During setup of the Polar, you can choose between three activity levels for your profile. Based on the level you choose, a daily goal is set for you. Unlike the Fitbit and Garmin, the activity goal can be reached in three ways (intense or moderate exercise, or steps). For example, on days I do a cardio based workout, I typically reach my activity goal by the end of the workout. On my rest day, I may have 12,000+ steps yet I still have not reached my activity goal. On a strength training day, I accomplish a large percentage of my activity goal, but I might need to take a walk around the block to meet the goal. With the Garmin and Fitbit, I would often begin my day with an intense 500+ calorie burn workout and still end the day without reaching my goal because I didn't get the purposed number of steps.
The Polar A300 has a number of advantages over other fitness trackers. Here are some that stood out to me:
* It's waterproof;although Garmin devices are also waterproof, Fitbit is not.
* Battery life: I am going 2-3 WEEKS between charges even though I use the Polar connected to a heart rate monitor for at least an hour per day. The other activity trackers that I tried required charging every 3-5 days.
* Heart Rate Monitoring: Wrist based heart rate monitoring is simply not as accurate or dependable as a chest strap. With both the Fitbit Charge HR and the Fitbit Blaze, a good sweat would prevent the device from detecting my heart rate. The heart rate on the Garmin Vivosmart HR was always lagging or just plain wrong (way off). Neither of these will pair with a chest strap. At first I thought it would be useful to know my resting heart rate; a head-up when I'm over training or getting sick, but with the way the Garmin averages the resting heart-rate, it doesn't work for this purpose. I also found that I am very aware of an increase in my resting heart rate and I don't need a device to show this. There was no real benefit to 24 hour heart rate monitoring.
The Polar A300 does not do 24 hour heart rate monitoring or even wrist-based heart rate monitoring. It connects to the Polar H7 chest strap. Even better, I've been able to pair the Polar with my Scoshe Rythym + arm band Scosche RHYTHM+ Heart Rate Monitor with Armband, Black since I'm not crazy about wearing a chest strap. I can choose the type of activity that I am doing and set the watch to record. I can also pause the workout on the watch, view the current heart rate, heart rate zone, time, and calories burned. (Note that you do not get smart notifications if the watch is in workout mode, a feature I love).
The Polar A300 does not calculate a resting heart rate, but it does do something better: the Polar OwnIndex Fitness Test (similar to a V02 max test) to measure cardiovascular fitness. To take this test, you simply put on the chest strap and lay still for a minute or two. The first time I took this test, my score was a 42 (which was great for a 36 year old female!). The app instructed my to take the test again in 6 weeks to see if I've improved. I'm looking forward to the next test; I like having a goal to work towards (beating my previous score).
* Smart Notifications: the Polar A300 does vibrate when your phone is getting a notification, text, or call. You have the option to answer or decline a call, but you cannot respond to a text (none of the trackers I tried offered that option). You only get a line or two, so you can't always see the full message. The Fitbit Blaze was slightly better for receiving text messages because you could read the whole message.
* Time to Move! One of the great features of the A300 is the "Time to Move!" notifications. Even after I reach my activity goal for the day, the watch will vibrate if I've been sitting for more than an hour. I found it so ironic that the Fitbits did not have this capability.
* Display: The time and date are always displayed on the Polar A300; it does not require some elaborate wrist movement to may the display turn on (and yet the battery life is still so much better than the other activity trackers!).
* Durability: This is a functional watch; it does not have a touch screen. I purposely chose the A300 over the A360 because I'm pretty rough on watches. I don't want to worry about scratching a delicate screen. I wanted something that worked well, not that just looked pretty and that's what I got. The Polar A300 has a comfortable band and seems to hold up to most anything. I read some reviews that the band was too long for some women, as it is unisex, but I have not found that to be the case. I have very small wrists and the strap does come all the way around my wrist, but it's held in place with the ring around the band.
I chose the A300 over the M400 because I am not a runner and I don't need GPS. More than that, I read that the M400 does not have a vibration feature. I haven't tried the M400, so I can't say for sure, but this was important to me.
Overall, this is a great device; it's perfect for my lifestyle. I highly recommend to anyone who wants a fitness tracker that can monitor workouts, daily activity, and sleep.

I own this watch for about 6 months now, and am very happy with it. It helped me to lose 32 pounds during this period and keep the weight in check! I've already recommended it to a couple of friends, and they keep loosing weight as well, with no special exercise plan, diets or money investments (I provide the details on how to make it happen below)

About the watch itself - first, on the plus side:
- it does have a battery that lasts for weeks;
- the white wristband has a good quality and retains it's pristine white color even after months of use (unlike some other white plastics that tend to turn dirty yellowish after some time), and even has some surprising "aromatherapy" benefit - it retains the smell of a shower gel long time after using it;
- Some complained that the band itself is too long, but in fact this is a good thing - it can accommodate to any wrist size, and I find it very useful when cooking or doing something messy without protective gloves - you can just slide it up the arm where it won't be affected, but will still count your burned calories;
- It calculates all the burned calories (including from standing, sitting or during sleep).

Drawbacks:
- I had a reddening on the skin and itching first days after starting to wear it, but it passed after a few days. To helps prevent it let the wrist band be not too tight (so it can move on the wrist easily), keep it nicely ventilated and wipe excess liquid from it if the skin gets wet (e.g. after being exposed to water).

Now about my success story of how to loose weight with it without diets or much exercise.

Background: I'm in early thirties. In May 2015 my weight was 75.9 kg (with height 174 cm, BMI 25.3), and I was so sure there's nothing much that could be done with it (while having a sedentary 9-5 office job and slowed metabolic rate that comes with age), that one needs to practically reduce menu to celery and carrots while exercising a lot. I was very shy because of the weight and had a very low self confidence. I evaded being on the photos, because they always made me sort of depressed, I reminded to myself a princess Fiona from Shrek, after she turned from a slim beauty into an ogre (still pretty, but overweight)...

However, in November 2015 I achieved 61.8 kg (BMI 20.4) and keep weight at bay for months now.

First, someone recommended to me to create a food diary on http://www.myfitnesspal.com (it's free). It turned out to be a smashing idea! It is really easy to use - it already has most of the food and drink items in their database (and allows you to enter custom recipes too, so they can be counted as well). You can select your weight loss goal - e.g. a pound or half a pound per week, and how active you are (or inactive). I recommend selecting half a pound (0.25 kg) per week, because it doesn't strain you too much or get you that sad feeling of being on a diet. It automatically calculates an every-day calorie goal for you. Now you just log and weight in the foods you're eating. That's it! I kept eating chocolate and white bread, and other stuff excluded from diets, only in smaller quantities. First week or two it takes a bit of getting used to, but then stomach gets smaller, and you won't feel too hungry anymore. Just don't get overexcited and put into a goal loosing a kilo per week or so - I have a friend who tried that, and it only turned out that after loosing her first 1 kg she felt starved, so she just stopped logging it anymore. Take it easy, and the weight loss will come naturally (and without stretches or loose skin). At first it's a bit tedious to log everything, but most of the products you use will be in your list of previously used items, so soon it will be fast enough to just pick them up from there.

Another advice - MyFitnessPal allows you to enter exercises too (though their exercise database is very sketchy still), and it awards you with additional calories you can eat if you exercised. It is the most effective for weight loss if you won't eat those additional calories it awarded you for burned ones. Weight goes away effectively if you under-eat 200-400 calories per day. Also if you do lose weight (and track it in MFP), you need to go into settings > Update diet/fitness profile and click "Update profile" with new weight - it will recalculate your calorie goal, because the less you weight, the less calories your body needs.

Now back to Polar activity tracker. When I achieved my weight loss goal, and now only need to maintain weight (there's a setting for that in MFP), I created a small table in my phone that I can refer to - how many calories you use per day if you did e.g. 30%, 50%, 70% or 100% of your activity goal. That way you can know how much you can eat per day, and not gain any weight! E.g. my minimal goal for every day is 50% of activity bar, which nets me about 1840 calories per day to eat. To keep this goal, I try to fill in small bits of activity - walking after work, jumping rope small periods of time, cooking, etc.

Yes, and for Apple owners, MFP can be synchronized with Polar (but I don't own Apple products, so can't say much about that).

Clunky, not pretty, looks like a satellite dish on my petite wrist...but I like it. I have taken months to decide on a new watch. I have had a Polar FT7 for several years, and barring the issue of it not having a simple stop watch on board, it has been a great workout companion. In conjunction with the heart rate unit that came with it (not a Bluetooth model) & my various Fitbit modules (yes, I have lost several in the last 3 years), I've gotten all of the data a recreational fitness geek like me has really "needed."

The development of some major leg issues that interfere with my preferred mode of exercise (Olympic-style racewalking) earlier this year necessitated that I switch gears and take up cycling. At the time I had no smartphone, my FT7 was fine for measuring HR, but Fitbit was less useful, even clipped to my sock. So, I began considering a combo GPS/ HR watch (and gagging at both the size and the price). I just couldn't decide. Garmin got great reviews, but because my Polar HR unit is still in working order, I could save some money by sticking with Polar. The wrist based HR watches, Fitbit or otherwise, just weren't selling me; I don't get the feeling the tech is quite "there" yet (...unless I want to wear my watch in an unnatural place on my wrist). Alas, as much as I loved the idea of wrapping many tech pieces into one, I did finally determine the features of the A300 were enough for me... when I finally decide to buy one.

Acquiring a smartphone last month, I downloaded the Map My Ride app- and voila! No more "need" for a GPS watch. Unfortunately, my FT7 decided to start acting up, requiring me to send it in, I'm sure, and Fitbit chose to go on a walkabout...again! So, last week, the time to upgrade & integrate arrived. A $22 credit on my Amazon account from some Apple ibook lawsuit brought this puppy in at just under $64. Perfect!

Having looked at the unit in several stores, I was aware it was going to be huge on my wrist...but dang! It is clunky and chunky and the graphics are anything but sleek. My first thought was "TRS 80," which will mean nothing to you if you didn't grow up in the 80s, well before "i" everything & Windows 95 through 10. Amazingly though, the soft silicone of the grande sized strap it pretty comfy. I never used to sleep in my FT7, but I can sleep in my mega watch just fine. And, well, at least I can easily see the watch face while riding my bike. The strap is nearly an inch wide, just slightly smaller than the width of the face (which, for me, is slightly narrower than the width of the pinky, ring, and middle fingers on my right hand all put together!), and LONG! Gads! I thought I was going to have to cut off an inch + worth of strap, but after messing with it some, I found the strap holder downer thingy will stretch/ slide far enough up the other side of the band to keep it down (on the plus side, it will also fit around my ankle!).

The button modes are essentially the same as my FT7, just with more data available with a few more button pushes. I LOVE the fact that you have to hold the button to stop a workout for three full seconds to actually stop it. I can't tell you how many workouts got segmented on my FT7 b/c of its 1-push stop function. It was quite irritating!

My only major concern, which almost had me repackaging it for return after my first long workout, was getting it to sync with my phone and/ or the Polar Flow website. I did everything correctly; I troubleshot over and over; a tech watch that I can't download data off of & link between fitness apps, isn't worth much to me. After an hour plus of frustration, I noticed the stupid word bubble icon at the top right of the Polar website. Running your mouse over it creates a red line under it. Whooppee! Polar! What does a red line tell a user? NOTHING! Nevertheless, I finally clicked on it, and lo and behold, this is where one goes to find out about any issues Polar is having with its servers, etc. And that explained everything. The next morning everything synced up just fine.

I love the Polar Flow app & website interface- one detractor though- Polar doesn't link with My Fitness Pal. BUT both Polar does link with Google Fit, which does. So, a little around the elbow to get to my ear, but no biggie. I'm not so young, or hip, or dependent on tech to function every day that that is effecting my small little life in the negative.

Well, my A300 just buzzed me & said to get my butt off of Amazon. Enjoy! Overall, I'm very happy with my purchase.