well this is a very hard question, but I think that Kisame stands as the winner in this one. Killer Bee has an obvious advantage with his raiton affiniti against kisame's suiton. He also goy humongus chakra like Kisame and the 8th tails and an obvious sword skill. Kisame is ranked as the most inferiour of the seven swordsmenn and is a force to recon with. he got the sword Shameda which feeds one chakra and like Chōjūrō said he is a beast without a tail and obvious has great sword skills. based on what I have said I think would give the victory narrowly to Kisame despite Killer Bee's raiton...