I have been religiously using my fitbit zip and I love it. It is a great motivator for staying active. I never realized how much sitting I did before fitbit. It is definitely worth the cost. Fitbit will have you logging your food and adding in more steps before you know it.
Drawbacks include that there are some activities that he tracker does not track well.. These you need to manually enter. Something like weightlifting and possibly spinning might be some of these.
If you get nothing else out of fitbit it will help you to determine why you are not losing weight. Most likely you are not as active as you think... And therefore not burning a lot of calories. I remember reading that the average person burns 2000 calories a day. Ummmmm not with our current life style. I think it is much a much less than that. Wear a fit bit for a day and get it to the 2000 calories. If you are a medium sized woman(120-150) that involves a lot of steps.
For my size I have to walk about 25000 steps to get to my fitbit calorie burn target.
