I'm using it for nearly a year now. Its really nice if the app can wake you up while you are in light sleep but sometimes you are just not in that phase during the 30min period the app tries to wake you in.

So worst case is that you wake up the same way you would with a normal alarm clock, but on the other days its pretty neat.

But the 30% battery charge I lose overnight is sometimes a hassle because my phone is either near the 30% right before I want to go to bed or I know that I have no time to charge it in the morning... and I refuse to charge the phone while its laying next to me :)