I'm still mixed on the Sleepy Cycle app. I seem to always wake up before the half-hour window the app's alarm has, then I fall back into a deep sleep, and the app has no choice but to wake me up instead of waiting for a "light" sleep cycle. The first day it worked great, since then, nothing. At least it lets me track how much sleep I'm getting every night(not enough).
Of course, on the bright side, maybe this habit of waking up before my alarm is evidence that my early-riser habit is starting to stick. I can only hope.