is it just better quality or are there going to be any differences other than that?
The movie experience is probably more entertaining in Imax because the screen pretty much covers the whole freakin' theater.
On "true" IMAX the screen will be huge (72.6 x 52.8 ft or larger) and there'll be more detail and vision definition. On "fake" IMAX it'll be just as good as standard digital projection.
the screen would be huge making the movie experience better...
The screen is bigger and some say better. As the others said, it is much bigger. I personally do not like movies on IMAX screens. I'm probably the only one who doesn't. You should experience it at least once just for yourself and what a better first time than with Revenge of the Fallen!.
bigger screen, louder speakers
there are going to extra scenes in transformers 2 just for i max