IMAX was AWESOME!!!!
Didn't look any different, but with 12,000 watts of sound and a screen that took up 90% of my lateral field of view (seriously), it was definitely worth the extra money!
Plus at 11:00 in the morning there were less than 30 people in the entire theatre. (of course I don't know why 3 of them had to sit RIGHT NEXT TO ME!!!!!
Also, Spiderman 3 will be on IMAX as well.