I dont base my purchases solely on review scores. I watch trailers, screenshots, read previews and reviews and base my purchase on all that together. For example Read Dead Redemption and Mafia 2 both look amazing to me and I'll get them even with low review scores.
Or: WKC always looked like crap to me and after low review scores I am 100% sure that this game is indeed crap, so obviously I wont buy it.
I also listen to what people say on forums about multiplatform games. I never trust people's opinions on exclusives.