What is your opinion on Proactiv?

I have a relative that has used this acne product before and felt that it was really good but a bit costly. I am not in need of it but I have a friend that has a teenage daughter with really bad acne. Have you ever used this Proactiv? How do you feel about it and is it worth the money? From what I have seen of the commericals the product sound real good but sometime commericals can make things look better than they are. Anyone got any opinions?