I personally am loving it. Alot to do, great story, great gameplay. I will say that there are quite a few bugs, but i havent really came across any that have broke the game for me yet. The game takes a wee while to get started too. The only thing i hate is full synchronization. I hated it in Brotherhood and Revelations, and it's no different here. I know you can ignore it, but i still feel it takes away from the freedom of the first 2 AC games when it comes to missions.
I think AC3 is a success, albeit a slightly marred one. Not a bad first try with the new game engine. I do hope they make another AC using the Anvil Engine, only this time building on what they have done right, and correcting some errors that remain. Overall i would definately put it in my Top 5 games of 2012 list
Currently playing: Crysis 3, The Godfather, Bioshock Infinite, Fifa 13