First I would like to say, it is sooo annoying to see a lot of people comparing it to Avatar. It isn't Avatar. In my opinion, this movie was way better in IMAX 3D than Avatar. The movie was fun and I loved all the details of Wonderland.
Another thing I see people saying is that the story made no sense and they thought it dragged on. If you are expecting some story that is perfectly sane, then obviously you have never read Alice's Adventure's in Wonderland. People are also complaining about the fact that it is not true to the book. This is NOT a remake of the book, it is a sequel.
Overall, a very watch worthy movie and definitely see it in 3D! I loved it and look forward to seeing it again.