I am having way too much fun with this game. This is what AC 3 should have been like with regards to naval combat and a frontier area. There are actually things to do in the open world and the assassination contracts are much better. Optional objectives aren't frustrating anymore.
It is great fun to run around the Caribbean with all the standard free running and combat abilities of the past game but this is a pirate game first and foremost. In fact it can feel like a ship boarding and harpooning simulator when you spend a lot of time at sea.
I'm only on sequence 5 but so far Edward doesn't seem to care for either group and only wants to get rich by any means necessary. He'll help the assassins because they'll pay him to kill people and he'll go after the templars because he wants their resources. He's very greedy and pretty apathetic to the templar/assassin conflict.
As a side note to some discussion above, Ubisoft has stated that the Kenways, the Auditores, and the Ibn La'Ahads are unrelated to each other but their blood lines converge in Desmond. That's why only he could activate the Grand Temple as he had the highest percentage of alien DNA in him of any human.