The movie absolutely lived up to the hype. The storyline was smooth and compelling, and never felt like it dragged, even though the movie was over two-and-a-half hours long. It was stunning visually; the interaction between live-action and computer-generated imagery was seamless. You don't have to see it in 3-D, but it sure doesn't hurt. Truly a cinematic experience.
I thoroughly enjoyed the movie. Dwayne Johnson is pretty good at the tough-guy-with-a-soft-heart role, and the movie keeps a good balance between tense action and comic relief. There's a cameo appearance from one of the "kids" in the original Witch Mountain movies, which was kind of fun to see.
I'd guess that younger kids would have a hard time keeping up with the storyline details, and parents who don't like exposing their kids to violence might want to be forewarned that the action gets kind of intense at times. But it was totally worth my moviegoing dollars. :)