The mom of a girl my daughter went to school with practices it (and she's a medical doctor as well) and swears by it. I thought about trying it, for a couple of things, but then my daughter and the girl fell out, soooo... I wasn't going to go in and wake up quacking like a chicken every time the doorbell rang.
I'm a believer, though, but like anything else, I think it needs the commitment of the person. There's no easy way out.