A few years ago I loved it. I don't know if they changed the algorithm but now it does the opposite of what it should. Generally seems to always choose the worst moment to wake me up. Some mornings I woke up within the alarm range, it didn't ring, I fell back asleep and rang while I was dreaming, so I always wake up groggy! I used the phone for a few hours last night and it still counted that time as deep sleep when I was clearly awake lol. They won't refund. Stuck with this bad app for 1Y