Lots of character introductions and story setup populates the first half. But once the film gets moving and a great deal of subterfuge clears, Rises is a great action/thriller. The plot seems complex and may have you scratching your head at some of the leaps in logic which are blurred by a lot of quick cuts, but it's pretty simple: bad guy wants to blow up Gotham. Awesome. Got it. I don't know why it tries hard to disguise that, but I appreciate the payoff that some, if not most of the setting up gets in the third act.
The one problem with Nolan's 'realistic' approach now evident in his entire Bat-trilogy, is the use of comic book cliche, which simply can't be avoided in a comic book story. Like a Chinese finger trap, the further the attempts at making things 'real,' the more strain there is when you simply have to ask the audience to suspend belief. Along those lines, there are plenty of comic book one-liners in the film which just don't work 100% in my opinion.
But I digress. The action was amazing and Hans Zimmer's score really made me feel the ferocity of the situation. Tom Hardy's Bane was a fully realized villain and the voice gave him a very iconic almost Darth Vader-ish presence. The new characters were pretty strong despite the tedious business of setting them up. Definitely see this movie and expect an intense, epic action flick.
p.s. The Imax scenes look amazing!