Their warranty only lasts one year, yet I've had to replace both Fitbit devices I've had twice within that one year. I'm now Fitbit-less because the latest, a Charge HR, failed for the third time, and it's out of that one year warranty.
To give you an idea of how bad the Charge HR is, its charging plug attaches with metal prongs, but it plugs into a slim plastic housing that is only glued to the rest of the device. The obvious result is that the plastic housing eventually gets pulled off with the plug. That's how two of my three Charge HRs have died. It'd be like if your laptop were ruined within four months because the power cable pulled off an essential piece of the laptop housing rather than detaching cleanly, and now it won't attach in order to charge. The third Charge HR bricked itself during an unprompted firmware update, which started randomly and then I guess got interrupted midway through when I moved my phone too far from the device. It never recovered.
I don't know what the hell they're optimizing for over at Fitbit HQ, but they're trying to sell $10 throw-away quality devices for >$100. It's outrageous. I actively discourage everyone I know from ever buying anything from them, and many other people I know have also completely sworn them off for the same reason. Their product just sucks.