Great when it works, EXTREMELY DANGEROUS WHEN IT DOESN'T. DONT USE! Sometimes (maybe once a month) I find myself oversleeping, then finding a "Missed Alarm" notification. I have been monitoring and testing this for the last few years. What I noticed when this happens is that that the alarm does not ring at all, and instead instantly throws a "Missed Alarm" notification. There's no possible way to miss an alarm either because the alarm doesnt stop ringing unless you specifically turn it off.