I've heard nothing but good things about it from mates, but have also unwittingly been spoiled on a couple of major plot points (one via mates partner talking about the movie while I was there for league, and again recently on the comments of a youtube video that was unrelated to the movie), so I'm thinking I'll just forgo paying for this at the movies and watch at my own leisure when available.
That's the problem about movies with potential twists and reveals that are intended to shock or surprise if you've been pre-spoiled, while you can still enjoy the film there is something diminished in that first viewing experience knowing what is coming compared to getting that legitimate shock/surprise which is an awesome feeling when watching for the first time.
Other examples where I enjoyed the film, but really wished I hadn't found out the key twists/reveals beforehand include Scream, Sixth Sense, The Usual Suspects, Seven (what's in the box) & Fight Club.