I believe the Fitbit is nothing more than a step counter type of device. I could be wrong, but that's what it looks like. The Bodymedia FIT has actual sensors,

I believe the Fitbit is nothing more than a step counter type of device. I could be wrong, but that's what it looks like. The Bodymedia FIT has actual sensors, it's an armband you have to wear. It monitors temperature among other things. It has been tested against, a $40,000 "portable oxygen analyzer", the gold standard for measuring calories. (source: http://www.bodymedia.com/the_science.html http://www.bodymedia.com/the_science.html) Regarding the Bodymedia FIT developer program. It looks you still need a subscription though and one still needs to upload the data from the armband to the website to get at it. Seems kind of pointless. I would want to get the data directly from the USB armband without a subscription.