Not quite what I hoped for
I was hoping that this device would actually wake me up at a good point but before I was already awake.  What I've found is that just as I wake up (am consciously aware of it anyway), the watch alarm then goes off.  I can't recall a single time in 2.5 months that it actually woke me out of a light sleep (at a possible waking moment).  That said, I have been getting up earlier since I started using the watch, possibly because it reminds me that I should not go back to sleep after a light wakeup.  If I were just basing my review on the above, I'd only give it one or two stars.<br /><br />But I gave it three because I'm finding that it does help me to assess my sleep and cross reference that with different things like if I had a late dinner the night before, if I exercised the day before, if I drank alcohol, etc.  This information combined with the Data A value (average duration of full sleep intervals) are useful information.<br /><br />All that said, I don't think this watch is for everyone.  And the software that comes with it is pretty basic and could be "A LOT" better which suggests that it was the minimal effort needed.  Makes me wonder about how serious a device it really is (as opposed to a gimmick).<br /><br />As others had noted, the vibration and audible alarms are not sufficient to wake people out of a deep sleep.<br /><br />If I knew then what I know now, I'm not sure I would purchase this again, considering it's price.
Rating: 3 stars