The Basis was the most sensor packed bundle of the lot and that is a device with lot of promise - two major issues for me:
- I never got used to the fact that it needs to be in Snug contact with your skin 24/7 for all the sensors to work this can get tricky when you sleep (for example) and the device is on on too tight
- No vibrational alarm A device that senses when you go to sleep does not have a simple mechanism to wake you up smartly - just stupid.
The Jawbone up was an unmitigated disaster - should never have been released.
My current device is the Fitbit which seems to have gotten most of the stuff right, but I still have to tell it when I fall asleep and when I am woken up. I also have the Aria Scale from fitbit.
As other commenters have echoed, the first device that will make it "totally frictionless" to record all the data will be a blockbuster.
My Ideal fitness device will also have a powerful camera that can take a fast snapshot of any food I eat, use magic algorithms to find a match to stuff known foodstuff (by using Image matching against a database of known foods) and automatically give me the calories and micro-nutirents of everything that I Eat/Drink.
Then we combine all this data with services such as WellnessFX & their Blood Markers...
Then we integrate implantable "micro-labs" that sample your blood 24/7...
Then we add in genetic data from 23andMe...