Bought my wife the UP (latest model) earlier this year (she requested it). Worked great for a month and then suddenly stopped responding. Jawbone had us send it back (we had to pay for traceable shipping) and they so kindly sent us a new one. New one would only record about half of the movement she did, so we ended up getting our money back (after paying to ship the new broken one back to Jawbone). I have not had any experience with Fitbit, so I can not comment on that.
