Just been to see it. Don't know what kind of reviews it got, but if they say its a bad film, they're wrong. It won't win any awards for being a cerebral masterpiece, but its still utterly, utterly phenomenal. I'm aware that people will probably want to see it, so no spoilers at all as its best that you go in knowing very little about it.
Basically, as gory shock and awe horror-thriller type films go, its up there with the best.