Just got back from seeing this.
It was really good. I was right in my guess as to what the twist was, but I was still a bit surprised about the other part.
This movie just reinforces the fact that Joaquin Phoenix is a really good actor. That Bryce chick was pretty good, too.
I think Mr. Shyamalan could have done a bit more of a build-up to the reveal. I wasn't quite shocked enough...but then again, I had a pretty good idea of where the story was going so maybe that was the problem. Husband was shocked and he agrees the build-up could have had a bit more to it.
The thing that gets me is all the people leaving the theater thinking it was bad. Here's a hint to those of you undecided on whether or not to see it: if you think "Signs" was a movie about aliens, don't see this movie. You will be sorely disappointed.
ETA: Another general tip: don't see this movie in a crowded theater. Our theater was packed, and the amount of people laughing and screaming was really distracting.