Just heard something regarding iMax and LieMAX on the movie podcast. They were saying the REAL IMAX supposed to have a screen about seven stories tall(76 feet tall). There is about 100 of that kind of screen in the world. If the iMax you are watching is not that big, you are not really experience the real iMax - just LieMAX
Not just the screen size matter, also the movie maker need to shoot the movie in IMAX technology in order to provide a proper iMax size image. 70mins of The Dark Knight Rises was shot in IMAX, it is in 70mm film (normal film 35mm).
If you saw a movie which is not shoot in IMAX projected on a IMAX screen, you are basically watching the a normal film projected to a bigger screen. You were in fact paying more for a lesser image. You are watching the same movie people watch in normal size screen.
what movie you should see in IMAX?
Raise of the Dark Knight
Mission impossible 4
Also, something about 3D, dont go to watch 3D unless the movie was properly done in 3D, like
how to train your dragon