I use to own one. It was the best thing to sleep on, imo. When it was cold, I could just turn up the temp on it and it'd warm up and if it was hot, like summer, I'd have it off and it'd feel so great because it'd be so cold. Ah, I miss those times. =P My freakin' cat punctured the whole thing with her claws. That bed will be missed.
@Cookie It's basically a huge-ass bag of water that you sleep on. =P