It’s okay. Just “okay"

I used a free website to generate noise for myself to sleep to. I decided to look for an app so that I could sleep to noise when offline, and not have to have Flash installed.
The best noise to sleep to is brown noise, but that’s not an option here. There’s also no way to add custom noises, so if you want brown noise, you’re out of luck.
You also can not play more than one noise at a time. I prefer to have brown noise and rain noise at the same time, oscillating at different frequencies. This only plays one selected noise. The developers have preselected noises that they’ve combined into one, but you’re limited by what they’ve already combined. Also, since they’ve changed the two noises into one, you can’t have them with different settings (volumes, end times, etc.)
The alarm sounds are mostly nice, I think you’ll find one you like and just stick with that, but there’s still no ability to add your own. Go with what they have, that’s your only option.

Shaolin Dave about Sleep Pillow