I'm going with Kisame here bros. Think of it this way, Kisame will start the fight with Samehada + swordsmanship + low level Suitons, while A on the other hand would most likely resort to V1. If you pit these 2 together, Kisame has the advantage as he can absorb the chakra spread in the armor. He's already shown to be able to do this against Bee and V1 Bee, who isn't slow at all mind you. However, A is going to figure this out soon and go V2 and possible pull off a Lariat. Problem with this is that Kisame can heal just like what happened versus Bee. Looking into the future of this fight, Kisame has 2(and potentially 3) trump cards he could use: Water Dome + Samehada fusion, his giant chakra absorbing shark, and PERHAPS 1,000 sharks to attack A. These 3 seem better than a speed boost imo especially when it's a bad match up.