I really like the sleep cycle alarm feature that attempts to wake you up at your lightest stage of sleep; it seems to be working for the most part. There are plenty of settings for customizing the alarm to your liking. The "spare alarm" is also a lifesaver.
Whats really nice is seeing your sleeping patterns visualized, with various statistics presented to you after waking up. Apple Health integration is also neat.
A noticeable flaw so far is that the battery meter on the status bar still shows through the night background, but the black text is hidden, creating a UI discrepancy.
Kediri the about Sleep Meister Lite