Among plenty of alarm clocks available on the Appstore this one will not bother you with any graphics, statistics, asking to put the iPhone near you while you sleep etc. It just advices you when to go to sleep if you know when to wake up, or tells you what is the best time to wake up at if you go to bed right now. So these are two modes of the Effeсtive sleep - Alarm clock. I found the second one very nice and I feel much better following it's advices for several days. You can choose one of 7 melodies that will wake you up in the morning. Also the alarm clock supports both 24h and 12h time formats. The only thing I would personally update is adding an ascending sound while the melody plays. Though there are some great slow melodies which are really nice to hear in the morning. Generally this app is cool.