When I first got it I had the headband adjusted way too tight. After a couple nights I got it adjusted correctly and now I don't even feel it. It doesn't leave marks when it's adjusted correctly ... it should be fairly loose. You'd be surprised, but it doesn't come off in the night.

The way the alarm works is this: You set it at the latest time you can get up, and then it will wake you up in a time period window before that where it's easiest to get up. The default window is 30 minutes, but it's adjustable. If you've gotten the proper amount of sleep, your cycle will usually present an easy-to-wake up point sometime within that 30 minute window, and it will begin the alarm at that time. (The alarms are quiet at first, and selectable from several soothing sounds, so it lulls you out of sleep).

If you haven't woken up by the set alarm time or if your cycle never presents an easy-wake opportunity, it will sound the alarm at the set alarm time regardless.

All sleep data is stored on an SD memory card which you can then upload to the website. It will ask you questions about your previous day, and correlate your sleep data against the answers. This helps you identify the things in your day that are interfering with your sleep at night.