Almost perfect.

It does what it says. I never wake up from a nap groggy anymore.

Two quibbles for the fifth star: I feel it wakes me up too soon, if I nap in a bed and leave the phone next to the pillow as I do with sleep cycle: a function to set or at least test sensitivity, like in the main app would be great. I would also love, if I got the chance to turn off notifications from within the app, again something that Sleep Cycle already does.

Kallinteris about Sleep Cycle power nap, v1.1.1