I went into this movie expecting something like the Hangover: An over-hyped movie that while not being great, was still pretty good. I think this one may have actually lived up to the hype, though. The movie switches from full CGI to live action throughout the movie, but the CGI is so amazingly done that it doesn't really seem that way when you're watching the movie--it's just changing scenes like any other movie.
The plot is old traditions given a new twist, and is great. It is not super complicated, but complicated enough to get you involved and make you worried for the characters.
I think the most simple, best thing I can say about the movie is that it doesn't feel like a 2hr 40min movie... It feels much shorter.