Cait Sith by far. He's a fun character to use in my opinion, and I love Slots. I know that one of them can kill you, but I don't think that ever happened with me, and I don't mind him (SPOILER)being a traitor at first because that simply part of the story. I understand that (SPOILER)the fact that he captures Marlene makes it hard to redeem him, but because that never really goes anywhere, so I would be surprised if that's all SquareSoft could think of to ensure you kept him around long enough to redeem himself.