MI: Ghost Protocol should be the new default IMAX theater demo reel. The cinematography, stunts, and especially sound were simply jaw-dropping in that setting. It is definitely worth the extra buck or two versus a "regular" theater screening.
Story-wise, the film was a solid "meh." Despite the "Ghost Protocol" agency-disavowal reference, the carrying out of the mission is indistinguishable from any other installment. Unlike previous MI films, which portrayed all IMF agents as super-human and always-professional, MI:GP relied upon the timeworn device of the fate of the world being in the hands of a mis-matched band of misfits. The little band of IMF agents includes: the rookie, the revenge-obsessed lover, and the redemption-seeking fallen agent in addition to the bullet-proof Ethan Hunt.
Still, the story is funny, exciting, and in the best tradition of MI films, just confusing enough to keep you guessing. It's the "IMAX Experience" that elevates the film to the must-see category.