SleepTracker?

This headline came across my PC from Crave: 'SleepTracker' watch knows when to wake you so I just had to track this down. The website for the company that makes the watch is at http://www.sleeptracker.com/. It's an interesting concept, give the watch a 90 minute period window in which to wake you and it will go off at the optimal time. You're supposed to wake up refreshed instead of groggy. If this really worked it'd be pretty cool. Do you have any personal experience with one of these things? Should I get one?