I have a Fitbit. I got it because I wanted to collect some data about myself and I liked the simplicity of the set-up. I also asked around and Fitbit seemed like the most “open” platform for collecting one’s own data. You have to pay $50 for a premium account, but after that, they allow you to download your data. Or do they? I looked into the details, asked a buddy or two, and found out that you actually can’t get the really interesting minute-by-minute data even with a premium account.