I saw it today. What a great movie! I agree with Roger Ebert, though...those that haven't read the books will be incredibly confused. Cuaron left out a bunch of the book's main plot to make the movie shorter. If you haven't read the book, prepare to have someone who has explain after the movie is over.
As for the directing and acting...superb. These actors are getting better, and that's saying a lot!
-Lasereth