I'm going to take Neji. The byakugan and sharingan make both of them exceptional taijutsu users, BUT as little as one single blow from Jyuuken can completely cut off Sasuke's chakra system and mess him up big time. I think Kidoumaru found Kaiten's weak spot because he's a genius, and also because he was able to observe from a distance Neji's weakness, because Kidoumaru was a long-range fighter, which Sasuke is not. I don't think there's much of a chance Neji will be affected by Sasuke's fireball moves, and since Chidori takes so long, Sasuke can't use it in a surprise ambush, and if Neji blocks the Chidori, I'd have to say it's over for Sasuke. He'd have depleted a maximum of half his chakra with one chidori, and if Neji dodges it, the fight is over, 64 hits later.