3D IMAX was interesting, stunning at times but in the end distracting, uncomfortable and gimmicky. I don't agree with Cameron that this is the future of movies. Blasting the sound track beyond tolerable levels doesn't add to the experience either.
As others have said, silly story themes stolen from vast number of movies made it very predictable and preachy. True to movie tradition, lots of inconsistencies (e.g. why do bullets not penetrate fighter jet windows and kill but arrows do?).
Definitely an event movie that should be seen but not even close to being the best thing ever done.