Pretty straightforward, not “what faction do you win as?” But just favourite generally to play, fun mechanics, theme etc.

Mine is probably the Mentak, I really like their pillage ability and faction techs. Having alternative ways of getting income other than trade is just very appealing. When playing them irl on the table as the literal pirate faction and extorting people then watching the reactions and pushing how far you can go with it, such as doing a trade with someone and then using pillage immediately to gain money back, is just very TI in my opinion.