I've seen this both ways---and I have to say that IMAX "Experience" is the right way to describe it. I wasn't as focused on the plot when I saw the IMAX version. You just are "pulled in" and viscerally wowed by the action, so the story points are fuzzy (Who are thoses hostages? How many people did the DA "kill"?) It was only seeing it the second time on a normal screen that allowed me to figure out the narrative links.
This was as exciting as everyone says and Heath L.'s performance is astounding. But it's also a smart critique of the hopelessness of Bush's so-called "war on terror"---one predicated on the fear of chaos and characterized by a "torture is okay" attitude, but one which only produces more chaos. As the Joker says, when a truckload of soldiers get killed, everyone accepts it because it's "part of the plan," even if it's a very bad plan.