It's a blisteringly entertaining film; compelling from start to finish. With every excuse to have a few patches of dry spots -- an issue I had with The Hurt Locker -- it's remarkably well balanced and relentless in its forward-movement.
On that note, a viewer probably enjoys it more the more they know of the events surrounding the raid. Not because of the truthfulness, of course, but rather because it avoids confusion: I credit Bigelow for pushing forward, never stopping to have an operative explain something to someone purely for the sake of the audience, but there might be a moment or two of confusion as the story hops around places and time. Perhaps I'm wrong, and a touch of mystery isn't a bad thing, but just something I thought about as it unfolded.
Chastain is great in a pretty thankless part, and Jason Clarke is also pretty wonderful. But this isn't an actor's movie. What it best accomplishes is a believable understanding of how the whole thing went down. The trajectory is never totally clear and the transformation of characters and situation is (purposefully and properly) under-explained. This is a movie about the killing of OBL and nothing more.
On that front, I have no idea how to rate the damn thing. In terms of flawless craftsmanship and entertainment it is better than anything I saw in 2012 or 2011. In terms of substance? Hard to say. I'll need to see how it all sinks in. But it deserves your time and money -- even if you don't think you like this sort of thing.