Georges St. Pierre or Anderson Silva?

Well my cousin is one of the trainers for Georges St. Pierre and personally he's my favorite fighter. He's got accurate punches, kicks, and take downs. When I've talked to him when I first met him, he's said he's done 4 years of Tae Kwon Do as a teen, Muay Thai pretty much his whole life, wrestling and B. Jujitsu for a number of years. Anderson Silva pretty much has the same amount of training and experience as St. Pierre does, but I've always questioned who'd win in a fight between. In my opinion, they're probably the two best fighters in the world.