I bought the Bad Elf Pro since I had a vision of using my iPhone in GPS only mode for field work. I have a CDMA iPhone 4. If you turn off the radio, the GPS goes off too. The Bad Elf Pro has allowed me to take my iPhone out into the field and locate myself on custom-made field maps (using a 3rd party app to display geoPDFs). I've used the Bad Elf Pro for two complete field days, in bluetooth mode, without recharging. My iPhone, which is almost two years old, lasted many hours longer than keeping the cellular radio on. I also found that the Bad Elf Pro provided far more accurate positions, right away, as compared to the internal iPhone GPS.

My basic usage of the Bad Elf Pro is as follows:
* Data log track to know where I've been using my iPhone (or back at the office) and, back at the office, to geotag photos from a quality stand-alone camera
* Locate my present location on a custom map

But an update on Feb 15, 2013, now has numbered Point of Interests (or waypoints). So now it is fully field capable as I can tie field notes (either entered via spreadsheet or an actual field book) to a point of interest and to a position on my data log track. I really look forward to using this feature!

I perhaps did test to see just how well the Bad Elf Pro works under rainy, canyon, shady conditions: data log track of my trip from Lahaina to Hana and back around the South Road. It picked up every single twist and curve and, for more than 4 hours, never lost a solid track (e.g., I've had tracks on other GPS units suddenly jump miles away and back to my location due to bad topographic and veg conditions). Fantastic! And every photo geotagged perfectly! Apple's Aperture does successfully import the resultant GPX files. I should add that the GPX includes elevation so you can view your track in 3D. But it is a satellite elevation fix, so expect it to be off by 40-80 feet due to limitations of satellite triangulation of elevation.

The Bad Elf Pro is going to revolutionize the way I take field notes. I can download the GPX or KML files straight to my iPhone or iPad, overview my day's work, and skip a lot of post-processing steps. Heck, I can take my wifi-only iPad out into the field now if I ever get a rugged case and sidepack for it! I can imagine buying a less expensive iPod touch to use with the Bad Elf Pro just for field work and not putting an iPhone or iPad in harms way.

Awesome product! Unless you need survey-grade positions, who needs Trimble when there is the Bad Elf Pro and great 3rd party apps that can provide 10 times more functionality than TerraSync? Bad Elf has great support and regularly update the Bad Elf Pro. They *really* listen to and appreciate customer feedback.

I'm amazed by how long the battery lasts. On an long haul 12h flight with the GPS tracker on all the time and well before the flight, I only used 1 bar ! That is incredible !

My 5 star rating is mostly based on my friend's elf and the anticipation that mine will work as well. His worked awesome. However, my experience so far has not been so flawless. It started out with my experience right out of the box. You're supposed to charge it right away to 100% before use. I did so, or at least I thought I did. I plugged it in and nothing happened (that I could see). Then I downloaded the app and synched the elf for the first time. According to the app my elf battery was at 100%. I thought since it was already at 100%, maybe that was why I didn't see any indication of charging when I plugged it in. I took it on it's first couple trips which included a circumference of 2/3 of the globe and about 20 hours flying time. I experienced several instances where I lost satellite lock My friend's did not. I also noticed my battery stayed at 100% a long time then jumped to 75% in an instant. It stayed at 75% for a few hours and then dropped to 25%. Again, in an instant. When I got to my hotel room I decided to leave the elf on till the battery died and try a full recharge. I plugged it in - nothing happened. No indicator light - nothing. I checked the outlet, both ends of the cord - nothing. I plugged the power cord in three times with no change. On the 4th time, however, the screen came on and said charging. It's important to note that two of the times I had it plugged in prior to the screen coming on, it was sitting plugged in for a couple hours each so it didn't just come on during the 4th attempt because the battery was dead. Why the 4th time and not before? I don't know. I checked each time to see that the plug was seated properly. It certainly seemed to be. I now unplugged if several times and replugged it in - each time the screen lit up and said charging. Weird. Now I've taken it another 1/3 of the way around the globe and the battery is still at 100%. I didn't experience a loss of satellite lock either on this trip. I will take it completely around the globe a couple more times to see if my problems have magically fixed themselves or not. I will update this review with the results. One thing I do recommend - buy the little screen protectors.

I have the non cellular ipad and my location (using Foreflight) does not show up on over water flights, i.e NY to DR, BVi, etc.. I used someone's Stratus and it worked on and off, but didnt work at crucial times. The Elf was able to continuously show my position on the ipad the whole time on a recent nearly 4 hr trip. The battery seems to last a long time - didn't need to charge it all and it paired with my iphone and ipad without any issues. It's doing just what I wanted it to do, so I"m satisfied.

4.5 stars, if I had the option. The unit performs as advertised.

I have had the GPS Pro for a few days now. I bought it to do paperless geocaching with an iPad 3 and several 4th gen iPod Touches. It Bluetooth paired with everything fine, and worked with all the mapping/geo apps on our ipad3, but the ipod touches were not passing the received GPS data into any apps. I emailed Bad Elf's customer support this morning and they responded extremely quickly with a number of suggestions, making sure location services were turned in the touches on and rebooting/power cycling the touches. Rebooting the ipod touches fixed the problem, and is something I should have tried as standard troubleshooting without needing to contact them.

I was able to go geocaching in the woods yesterday with the BE GPS Pro and an ipad 3. It worked well with my offline geocaching app (Geo Bucket) as well as my offline topo map app (GAIA GPS). My comparison is a 10 year old Garmin GPSmap 76S GPS receiver with an external antenna, which I compared it to. The GPS Pro GPS receiver is much more sensitive than my old Garmin, as it gets a signal in my basement, whereas my old Garmin will not receive in the house at all. Subjectively, in terms of outdoor accuracy, the Garmin (with the external antenna) might be a couple feet more accurate, but it is hard to tell. I was satisfied with the GPS Pro's accuracy, it seemed to stay in the 10-15 foot range.

My only complaint with the GPS Pro, which I dinged it a half star for, was one remarked on in the early online reviews, the tethered plastic port cover for the charging/data mini USB port is very loose and falls out by itself, compromising splash and dust resistance. One other issue I read in an early online review was that the backlight could not be turned off, but that is not true, a brief press on the power button toggles it on/off.

The only other issue I have with the unit is a philosophical design issue with outdoor electronics - I do not like built in rechargeable batteries. I would much prefer replaceable batteries in a battery compartment, so that I can replace depleted rechargeable AA or AAA batteries in the field and have the unit continue to work. In a few years, the battery will go bad and the unit will need to be sent back to Bad Elf for replacement, or I will need to go through the cheaper but riskier process of figuring out how to do it myself. Just because Apple made that bad/$elfish (IMHO) design choice does not mean that others have to follow.