I’ve got one…had it for a couple of months.
Got a bit bored of it now (don’t tell my wife).
The sleep tracking is useful as I don’t sleep very well most nights, and it helps work out why I’m knackered in the morning when I think I got a good night’s sleep.
It has a vibrate alarm which I use – I get up an hour and half earlier than my wife, so this is better than a loud alarm. It also wakes me up when I’m ‘in light sleep’ in a 30 min window.
The sleep tracker is based on movement, so it’s not particularly scientific, but it’s not bad.
I might upgrade my Ambit and get the latest as this has activity tracking built in, but continue to use the up for sleep tracking and vibrate alarm.