There is a $.99 iPhone App that does essentially the same thing using the phone's accelerometers, etc. called Sleep Cycle http://www.mdlabs.se/sleepcycle/ It definitely seems to have had a positive impact on my mornings. Less biometrics than the Zeo probably, but certainly more economical if you have an iPhone.
I got a Zeo recently, but mainly to try to get answers to a question that isn't generally applicable (specifically, how blood sugar interacts with sleep). I don't really buy the validity of using an accelerometer as a proxy for sleep stage, but if your goal is just to get woken from light sleep rather than deep sleep, there's an Android app called Gentle Alarm that does that using a pre-alarm: a soft alarm sound played 30 minutes before your scheduled wake-up time which, in principle, will only wake you if were close to awake already.
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