Just got back from seeing it in IMAX ...
... wow. It was absolutely amazing. I wish the entire movie could have been shot in IMAX.
Sadly, the non-IMAX scenes were sent through the same God-awful processing they use for the "IMAX Experience" versions of movies where they crop it to fit the screen (I'd hoped they wouldn't because the 35mm scenes were letterboxed), but it wasn't a big deal, and it just served to make the IMAX shots look all the better for it.
The shot of Batman standing on the destroyed building's rubble while firemen put out the blaze behind him is instantly iconic, and when you see it in IMAX, the feeling is amplified by about fifty.
If you can, see it in IMAX. Definitely.