At first, I didn't like it because of Sequence 1 and Sequence 2 (until the end of Sequence 2, that's when it started to get fun).
I'm having buttloads of fun hunting, doing missions with Connor, and the new Notoriety system is awesome! It has levels of Notoriety instead of percentage. Once you hit level 1 Notoriety, you're going to start getting in danger.
A funny thing happened to me in Sequence 5. I needed to enter a Printer's Shop for reasons I will not reveal in order not to spoil the game. There were two guards right in front of the door and I was at Level 1 Notoriety. However, I dropped from the rooftops and because I was pressing "B" (Circle for PS3 people), Connor automatically opened the door without touching the ground.
The funny thing about that was, the guards detected me as soon as I opened the door and engaged in combat. The combat music started, but I was already entering the building, so it went into a cutscene and when I was done, I didn't have to fight the guards.
Anyway, I love AC3 so far. The story is really intriguing and the new controls are nice. The only issue I have is the running animations. I really don't like looking at Desmond's butt wiggling in front of me as he starts to run. >.>
Regardless, this is definitely a good game.