Hey Matt,
I'm pretty interested in the band and I preordered mine from the UK so I can tinker around with it in April.
Specifically the sleeptracking is interesting so I'm absorbing all the info I can get right now.
You say that the Band may see the REM sleep as "light sleep" - but it's correct then from what my understanding is.
Your link is pretty interesting and somewhat difficult to absorb (non english native speaker here :-D) but even the graph shows the REM sleep on top of N1 - N3. So from my understanding the Band tracks the HR and motion of you (and maybe the "stress level" of the GSR?) to get an overview of how your body behaves. Because it can not properly diagnose everything like the sleep labs can, it has to interpret that data.
I read your screenshot and compared that to all the pictures in this thread.
Four to six cycles should occur during one night.
Therefore, your screenshot shows 7 segments between awake and sleeping / deep sleeping.
According to the website that you linked, the N3 sleep is the most restful and your heart rate is at the lowest point and your brain is as relaxed as it can get (slow brain wave activity).
So in theory, the Band should be able to check your HR every 8 minutes (2 of 10 minutes active) and get a pretty accurate result for REM, N1, N2 or N3 sleep based on what your average HR is.
I am by far no expert in sleep (I myself have trouble to get a proper rest and often feel tired or not fully "here") so it's pretty interesting to get a good insight of what is going on when I'm sleeping.
I'm just trying to make a picture of it. I know that stuff like caloric burn, HR and sleep tracking are not used for medical purposes (not from the Band right now) because the data may not be accurate to the spot, but it's good to get an overview and especially to get a trend.
I've started to exercise this year and I'm using my iPod Nano as a tracking device with Nike+ in order to know my trend on the crosstrainer. It doesn't matter to me if the caloric burn shows 500 and in reality I only burned 280 or 300 - the trend is important to me.
So I'm trying to get a hold of what the band shows with sleep track because I want to understand it when it arrives at my home.
It's great that you guys compare all that data, but what is interesting for me:
When the band shows you as "awake" - do you remember to be awake, or is it just "light sleep"?
I'm asking because OberstDanjeje shows nearly a full hour of "awake", so where does it come from?
I have two cats and one of them usually wakes me up during the night when she jumps down from the closet or something like that. That should definately give a pretty big spike in the band overview, right?
I'm gonna compare that sleeping data with the times where I remember being physically awake just to understand my lack of restfulness a little bit better.
(Sorry long text - just some thoughts and trying to understand what the Band is providing and what you are showing because there is little knowledge of the band and how it completely works)
Regards,