Jen0414 asked via MFP mail which of the trackers I have used was the most accurate. This was my reply which I decided to recycle and share with this group:

Well . . . that would depend almost entirely on your definition of accuracy. Sleep monitoring? Calorie counting? Step Counting? It also depends on what you do for exercise and what you do for fun. Then there is fashion to think about. Do you care about how it looks? Where you wear it? Are you iPhone or Andriod? What other apps do you use for fitness and/or weight management?

There is an imperfect perfect match for everyone. Accuracy per se is probably one of the least important features as any one of them will be consistently inaccurate. What is more important is did you take 1,000 steps yesterday give or take 100 or did you take 10,000 give or take 1,000. Did you burn 1,500 calories give or take 150 or did you burn 3,000 give or take 300?

Any of them will almost certainly change your behavior for the better. Based almost strictly on the criterion that a tracker should be worn 24/7/365 (as much to keep from losing it or forgetting to put it back on as for complete activity quantification) I currently like the Vivofit. If all of your exercise consists of walking or running, a Fitbit Flex is a good choice if you can remember to put it back on after its weekly charge.