It *is* one of the best games I've ever played.
The combat system is absolutely amazing, and everything you expect Batman to be: it is simple to use, and you can do the movie/comic thing of wading into a group of seven or eight guys and just own them. Just four buttons gives you every conceivable strike under the sun, insanely fast counters, throws, flips, and ground strikes. There are challenge modes (not in the story) where you just fight gangs of guys.
This all pales in comparison, though, to the sheer cool factor of being able to drop down from a hanging object, grab a guy by the throat, reel back up, and leave him hanging as you swing off somewhere else. His buddies come over to check, you sneak up behind another one, silently choke him out, and make your getaway while everyone starts panicking. It really plays up the whole fear persona that Batman operates on, and the game will absolutely punish you with oppressive gunfire for not doing it this way.
Add to this the cool, yet totally functional and necessary gadgets you get to use, the constantly unraveling challenges you must solve, the detective mode that helps you hunt down clues and objects of importance, and all the side puzzles that the Riddler left behind, and I can see I will be playing this for a while.