I have one after my wife's jugsy kickboxing friend showed me her fitbit. I really like it. I've had it about a year or so. It has held up really well to the abuse I have put it through, including a couple of trips in the wash and one trip in the pacific ocean. I have the little one that clips on you, not one of the bracelets (I just looked it up and it is called the ONE). I find it fun to keep up with the step count thing during the day. I've managed to lose about 20 pounds over the last year with very little effort. I think 10 of those pounds were lost in the last month as I have been back to trying to walk more and eat less. My wife has the same model I do, and she recently bought their WIFI scale (Aria is the name), which is also pretty cool.
FWIW, I find it works better when you have some friends on your fitbit profile so you can compete with them on step count. I have jugsy, the wife, her other jugsy non-kickboxing friend, jugsy's sister, and my sister in law.
I just noticed this thread was pretty old. Oh well. Maybe we should great a MWGL fitbit group so we can out walk each other. It might be fun, "I have more steps than you and you have bad toanz"