I use this in conjuction with the P90X program and can change my weights quickly for the next exercise, allows me to maintain my cardio pace and achieve a fulfilling complete work out!
I have two pairs of 552s and one set of 1090s now. I do a set of cardio bodybuilding routines where I need 3 weight pairs to use one right after the other. These work very well for me. The only thing better would be a better sync on the weight settings. Sometimes they snag a lower or higher weight when choosing and they wont pickup. Easily fixable but a nuisance.
I found most of the comments, pros and cons, about the SelecTech dumbbells to be accurate. The flexibility of the product is incredible, and this by far outweighs any of the drawbacks, including the length of the dumbbell which has not been a distraction for me. The video that accompanied the SelecTech dumbbells has been equally impressive and has helped me to design my workout to target specific muscle groups. The 4 Step Rep segment at the beginning of the video is incredible, and by using this technique, I actually decreased the weight on the bumbbells and have seen better results by doing the excercises correctly.
Pros: Compact, Durable, Easy To Use, Multifunctional, Targets Muscles