Started playing this today and got about 3 hours in. First off, the graphics are pretty amazing in this game and although I'm not a tech junkie when it comes to graphics, its even with Uncharted 2 as the best on any console IMO. The scale of the game is also quite ridiculous, especially during the very beginning. Gameplay also seems to be improved in areas, with the new blades being much more combo friendly. The second weapon I got is also quite fun to use as well. The only issue I have so far is the fixed camera angles, but it isn't really that bad.
Very minor boss spoilers (no names involved):
The first major boss in the game is no fun and kinda cheap/difficult IMO, but the second is a blast to fight against. Both are very cool looking in their own way, but the second boss is just a complete badass. Probably one of the best bosses this gen IMO.