I really enjoy these. They have helped me do more in my apartment when I don't have a lot of time, space, etc. I used them everyday for a couple months and had no real issues after getting them (I only broke my streak due to travel for work). They are enjoyable to use even if a little awkward. I was concerned about some of the other reviews, but I really haven't had any issues so far. Yes, they can be less smooth or familiar than other weights, but it is a minor trade off to me for the convenience. I can change weight rather quickly, but I just keep them out of the way and treat them well when I am using them and they have been fine. The grips do not hurt my hands and I have not had them drop plates or anything although I could see that happening with age if you don't treat them well. They also come with a nice little instructional dvd if you want a visual to improve your form for using this product even though you are probably already familiar with the exercises. They also allow you to do some nice, nuanced motions since you can weight the sides differently to change your repetitions. This is really nice. I also like the novelty/nicety of using them. I thought this was a little silly at first, but it really keeps me coming back to them and helps me enjoy even brief sets on days when it is hard to fit in. So, I appreciate the extra motivation to use these over a more typical dumbbell design. They are worth my investment.

I got these adjustable dumbbells since most of my workouts are done in the garage ever since we had our first baby. With very little time to get to the gym I needed these to maximize the time I do have to workout now. I found these to have no movement when I changed the weights. I've used different sets of these in the past and that was my biggest complaint. I would feel the weight discs moving when I did curls but not with these. I highly recommend the Boxflex brand. I also upgraded to a new test booster called Tritestin by Biotek Nutrition "“ Testosterone Booster Boosts Test Levels and Increases Strength, Muscle Mass, Fat Loss, and Overall Male Performance which increased my energy and sex drive to super high levels. I had to figure out something since my sleep patterns are way off which causes my energy levels to drop big time and affects my sex drive. The combo of the new equipment and the test booster is exactly what I needed to stay motivated and still get good gains without going to the gym.

Bought these for P90X3. They are great for most workouts but the large physical size of them makes some of the moves very difficult. There is one exercise where you are on your side, propped up with one arm, and you need to pass the weight between your torso and your arm that is supporting you on the floor. Easy to do with standard weights but since these are quite a bit longer, additional wrist movements were required to pass the weight through the window created between torso and arm. Otherwise the weights are great.

Firstly, on a superficial level, these things are pretty. While it may be irrelevant to some, most people looking to save on space might be required to have these in their space. They look sharp. Hands down the best looking adjustable dumbbells.
Aside from that, they function very well. Easy to understand. The time it takes to change into another weight can be your rest time between sets anyway.
The con would be that the material of the weights themselves is not indestructible. It would surely crack if dropped on the wrong surface. I don't believe there is any purposeful reason for weight drops at a weight this low, but accidents can happen.

Just got them today but have been eyeballing them for awhile now. Kept finding myself needing to buy more dumbells plus the space where we kept the dumbbells we had bought, kept growing in footprint. Couldn't wait to unpackage them are start trying them out. I saw there are instructions and a DVD but I didn't open them yet. Just started playing with them and trying them out. Initially I was thinking you just had to turn the dial on one side in order to change the weight but you actually have to change it on both sides. Not a big deal at all. The dials turn easily but you can feel the "notches" when you get to whatever weight you're adjust to.

Just did a small workout with them but have a full workout scheduled for this Saturday but can't imagine that I'll be unhappy with them. If anything changes, I'll update the post but for now...I'm very happy I bought these and just wish I had bought them sooner!