Ease of use
Design and form factor
I really like the FitBit One. It's the only fitness data tracker that also tracks sleep. The website that FitBit syncs to is pretty great, although sometimes it is hard to get an accurate sync. Setting up the FitBit was kind of a pain, but once I got it set up it works like a dream. I have had to put it in my pocket instead of on the belt clip because I'm always afraid it's going to fall out. The clip is pretty strong, but knock it hard enough and it will fall off.