I thought the action was miles beyond Batman Begins. The fights were shot better and definitely showcased Batman's fighting style better, but more importantly they were more interesting. Batman simply acted more like Batman--he did things that were more impressive, more inventive. I especially enjoyed his assorted uses of the grapple gun; dragging the Batfake, dropping the clown-mask hostages, and my personal favourite: using the SWAT officer as an anchor.
There are just these things he does. Batman things. For example, when he glides into the construction site/abandoned building (whatever it was) and dives into the Joker goon (well, hostage, but you know what I mean). I loved that, as well as his glass-smashing entrance in Hong Kong. Also, I enjoyed the shot where he grapples his way up to the Joker, and kicks off the side of the wall on his way up. That shot was neat, and it's just these little things that contributed to Batman feeling more like Batman.
The action scenes were just more intelligently designed, in the end. Batman leaping the Tumbler to intercept the rocket was great, as was in introduction of the batpod and the way Batman flipped the truck. The Hong Kong sequence, the fight in the construction site/abandoned building, all great stuff. Very exciting.