I've only played Assassin's Creed, Assassin's Creed II, Assassin's Creed: Brotherhood and Assassin's Creed IV: Black Flag.
I kinda liked them all to be honest, and for different reasons. I guess Brotherhood is the most derivative and therefore the worst of the ones I've played. I loved the pirating in Black Flag. AC2 had the best story, but it also started a lot of the bad traditions in the series. I like how AC1 had a more "day in the job" approach to storytelling. It's the only one where you play an actual assassin, taking assassination contracts. And I enjoy the parsimony of the gameplay.
I kinda liked them all to be honest, and for different reasons. I guess Brotherhood is the most derivative and therefore the worst of the ones I've played. I loved the pirating in Black Flag. AC2 had the best story, but it also started a lot of the bad traditions in the series. I like how AC1 had a more "day in the job" approach to storytelling. It's the only one where you play an actual assassin, taking assassination contracts. And I enjoy the parsimony of the gameplay.