From my experience i would have to say that Bucc and Corsairs are the funnest
I dont know much about pirates since i recently join the pirate community, but i think that sairs are stronger? (correct me if im wrong. thank you)
Personally cannoneer is probably my favorite out of the 3 pirates. It seems like the missing link to say between sair and bucc and has it's own playing style, especially compared to the other two after the mutiny revamp.