Revelations is my favorite though. Nothing like throwing a bomb full of sheep blood in the middle of a procession of citizens. And they can't even de-sync you because Ezio totally did that.
Anyway, I like Revelations because it has my favorite versions of Ezio and Altair, adds a lot of convenience mechanics (the hookblade, part hook, part blade), freed up the primary/secondary weapon pairing system, gave the series a heavy graphics upgrade from Brotherhood (which looked the same as 2, and tended to be kind of gross during close-ups), made it so I didn't have to interact with most of Desmond's annoying friends, and got rid of a lot of Brotherhood's jank (shop missions, bland recruits, ridiculous 100% sync objectives which I suffered through earning, etc.)
Only thing I don't like is the lack of horses (no place to ride) and Janissaries being a pain to fight at all times. Oh, and the stupid Desmond's Journey sidegame. Can't believe they made a paid DLC expansion for that.