By now you've read everything about this movie - a twist on an old/classic story, weak/stereotypical characters, etc., but visually stunning and moving enough to overcome its minor flaws.
I've seen this movie twice now - in Real3D & IMAX 3D and I may go back and see the Real3D again. IMAX has sold out and isn't worth seeing.
When I think of IMAX I see a huge screen, 7-trillion watts of audio power and the total immersion in the experience. Not so here. This movie is 'IMAX digital 3D' - the same movie that you see elsewhere, on the same screen, just pumped through an IMAX projector. Big whoop.
So see the movie, love it, see it again, but see it in Real3D and tell IMAX what you think of their sellout by not giving them your $$s.