How are you all finding it? Graphical bugs aside, which is to be expected with a new engine, I'm finding it better than both Brotherhood and Revelations and on par with Assassin's Creed 2.
It's certainly a lot easier to die because you cannot rely on counter-kills (which are incredibly hard to pull off if you're surrounded) to bail your **** out of each fight. You need to be constantly on your toes in a fight because if you only focus on the enemies around you you're liable to not notice the squad of redcoats down the road prepping a musket volley your way which will either kill you outright or severely wound you.
"Magic" medicine to heal you mid-fight is gone too. Counter-kills are not gone, they have just been HEAVILY modified. If you hit the parry button at the right moment time slows down and you get the opportunity to either Disarm, Throw, or attempt a counter kill. 8/10 times a counter kill will fail, it depends on the enemy type you're engaging. Depending on the tool you have set you also get the option to use it to start a killstreak combo - parrying an attack and using a rope dart to yank an enemy into a tomahawk-clothesline is a thing of beauty!
The story is good and does a good job remaining impartial considering the setting, if you come into this expecting a bombastic two-finger salute against the British then you might be disappointed. Connor, whilst nowhere near the charisma of Ezio Auditore holds his own and is at times an interesting character. Naval battles are insanely good and easily the best side-game the series has seen thus far.
I am only at Sequence 9 so far, I suspect there are 12 in total so I am nearing the end but have enjoyed it all the same. There are some really good plot developments that happen rather early that completely threw me.
Lucy was an Abstergo double-agent which is why Juno took control of Desmond's body to kill her at the end of Brotherhood.
BIG SPOILER: You spend the first 4 sequences playing as Haytham Kenway, Connor's father who comes to America to find the vault left by the first civilization. After amassing a small group of allies and assassinating a corrupt British Colonial Officer he is revealed to actually be a Templar. Did not see that coming at all.
How are you all finding it so far?