It was fun. The animal spirit powers were refreshing and brought a new perspective to the combat. The DLC didn't feel a chore for me, as I was returning to this game, just to complete this and the spirit powers played a huge part.
The DLC story is clearly not canon to the main game, but it was interesting as a "What-If" scenario.
Basically, King Washington gets possession of the Apple of Eden, which corrupts him and was also used to corrupt several others to do The King's bidding.
You will see several allies from the main game, return as your adversaries this time.
Before trying out this game, I was under the impression that these episodes were just to take advantage of the Native American mythology but the presence of the Apple Eden fits this right into the AC universe.
Definitely would recommend this piece of DLC to anyone who hasn't played it yet.