It sounds good but also more then i would want to spend. I think something cheaper would be more popular. Competition that's what its about:
$50 http://www.wakemate.com
$0.99 http://www.lexwarelabs.com/sleepcycle/

I don't know what would be most accurate or most cost effective or even if any of it is good enough to purchase. But if anyone has tried any of it please let us know.