I use sleep time for about 1,5-2 years. And at first it was great! It really helped me to wake up early. But for the last 6 months it stopped working:( alarm is ringing at the wrong time. But I guess that might be my personal problem. All in all I would recommend to try this app) azumio, thanks for developing this app!
Broonypie about Sleep Time+ Cycle Alarm Timer, v3.6