I've been wearing a Fitbit One for almost two years now. I'm not too interested in the motivational aspect, but use the data to back up health-related decisions

I've been wearing a Fitbit One for almost two years now. I'm not too interested in the motivational aspect, but use the data to back up health-related decisions. For example, I was able to use the data to confirm that getting exercise late in the evening doesn't affect my sleep (so no need to change my gym routine). I ended up building an entire service to support these kinds of analyses (zenobase.com), hoping to find enough people who care more about data than badges :-)