Definitely Caine. Not just his performance, but the material he was given is superior as well. Sure, Irons gave a heartily dry and sarcastic edge to Alfred. But the anecdotes Caine's Alfred gives are some of the best pieces of dialogue among the trilogy, especially in The Dark Knight.
They also create a rich context for Alfred that even the Burton's Batman failed to do. In the Nolan trilogy, we realize that Alfred had a life before he was a butler - one that was full of adventure and bad-assery. He is experienced, he is wise, and he has seen some shit - which makes more sense when you realize a butler is assisting sociopath dress up as a bat and take down the mob.
Although TDKR perhaps gets some flak around 4chan, all memes aside, there is no denying that the scene between Bruce and Alfred before Alfred leaves for good is heart-wrenching.
BvS is a tonal disaster, and the more I think about it, the more perplexed I am as to why a seasoned talented actor such as Jeremy Irons agreed to even do the film.
