I used to have a FitBit and sleep score is something I don't miss at all. For one thing, on FitBit anyway, sleep score only really varies between 71 and 90 (there was some discussion on the forums there on how to achieve 99 or 100, but that was like hacking the app, rather than improving your sleep), for another, it's a silly thing to have a score on.
There is a sort of sleep score on the V4 though: your body battery. If it went up a lot, you had a good sleep, if not, not. You *could* use waking BB - bedtime BB as your sleep score.
Finally, a note on body battery. Although there seems to be something in it, if the watch records more deep sleep (and I vary between 0 minutes and 1 hour, the latter very rarely) the less my BB rises overnight. No deep sleep can mean 100 in the morning, while an hour of it and I'm around 89. This seems very counter-intuitive. I do think the FItBit measured sleep better, although its quirk was that I had almost no REM sleep (I'm convinced I dream a lot), while the V4 has me in REM five minutes after I've got up.
Using BB is an interesting way of looking at it, but all I ever have is a negative BB except when I am sleeping and then it is a straight line. Haven't figured BB out yet.
and, they should add the same monthly reporting on sleep stages like the other activities. Over a month you can start to see trends of your stages. even up to 6 months. The PC Dashboard only tracks length of sleep time over 6 to 12 months.
