May not be the most popular choice, but I say Kakashi wins with REALLY high difficulty. To me, the things that puts Kakashi over the edge is not Kamui but his expirience. His analytical skills are some of the best in NV, as he has demonstrated many times before. And who knows, maybe because of his fight against obito, he might have figured out how to use Kamui like obito has, which Sasuke hasn't fought against before. However, Kakashi HAS seen his Susano'o and his arrow projectile thing, and probably came up with a couple ways to get around that. Like I said, his expirience puts him over Sasuke in my opinion.