I bought the Zeo Mobile because even though I was getting enough sleep most nights, I was still feeling groggy many mornings when my alarm woke me up in the middle of heavy sleep. I wanted something that would know when I was NOT in heavy sleep (REM or deep sleep) and wake me up then... Zeo seemed like the perfect answer.
So far, after a few weeks with Zeo, I'm not convinced it's much better than my regular alarm. Even after a 9- or 10-hour-sleep night, when the alarm goes off, I feel like I'm dreaming a lot of mornings, and as a result, I felt really tired. (FYI I don't have any other "sleep stealers" -- I don't drink alcohol or caffeine, and I sleep in a quiet dark room, so I'm 99% sure it's just when I'm being woken up). Looking at my sleep history, it looks like the alarm woke me up in the middle of REM sleep or in the middle of Light Sleep, but not in the in-between like it's supposed to.
Separately, I've tried the free Sleep Cycle app on my iPhone, it works by putting the phone on your bed, and it senses when you're moving around to wake you up (you set a 30-minute window, just like with Zeo). It is basic, so I was hoping something like Zeo that measured my actual brain signals to know when I was ready to wake up. But the free app actually worked better than my Zeo, and woke me up when I was half-awake and turning over, which was great. I could tell the difference, because each time it woke me up, I felt a little awake already and had the feeling of "wow, how did it know I was awake". With the Zeo SmartWake alarm, on the other hand, I have a feeling of "wait? what's that noise? am I still dreaming? oh right, it's the alarm". Now I'm considering returning my Zeo and sticking with the free app (which doesn't require you to wear anything on your head).
So what I'm wondering is... Why can't SmartWake be more like that? Why can't it tell when I'm in a half-awake state to wake me up at the right time, instead of in the middle of REM or light sleep? Or am I asking too much of it, something it can't do? I'd like to give Zeo a chance since it was expensive, but unfortunately it hasn't done for me yet what I wanted.