I am using a Fitbit Force nowadays as part of a focus on quantified self for work, but of course the data that it records is also interesting to me. It is a strange device if you think about it, because it’s really a glorified pedometer. If you truly wanted a pedometer, you could buy one for a couple of bucks at the dollar store. The Force will set you back $130.
From a tech POV, it’s novel because there aren’t many devices that are similar (but there are other players in this market too). It’s a piece of wearable tech that is beneficial and not too expensive. It packs a 7-day battery, OLED screen, vibration mechanism, pedometer, altimeter, NFC and bluetooth radio into the rubber wristband. I decided to get the Force over the previous model (Flex) because the Force had a clock display, and in general, a more detailed display (you can see actual counts instead of just a relative-to-goal indicator)
However, most of the tech is auxiliary, and the primary function is that of a pedometer. The hardware itself is not necessarily worth the 30x or 50x price difference between a dollar store version, but there is also substantial software around it. The Force syncs wirelessly with your device and uploads your data to your online dashboard. You can set goals, see your progress, and track your behaviour across days, weeks and months. I think that’s interesting and perhaps worth the premium.