Board Thread:Versus Debates/@comment-26636534-20150919130455/@comment-26636534-20150920205320

AsianReaper wrote:

Kakashi would still have to react, then activate Kamui. So Kamui would have to be faster to intercept at all, since the arrow had a head start and was so fast in the first place.

Before Sasuke fired the arrow at Kakashi, Kakashi saw Susanoo forming an arrow and loading it, logically then Kakashi predicts that this projectile is going to be shot at him, so he readies Kamui, since with his sharingan he can gauge the speed of the arrow to be fired and knows he can't dodge it.

This still isn't enough to definitively say that Kamui is faster than a Susanoo arrow, but it does depend on the distance traveled as well. Personally I believe that all MS techniques(single MS from what we've seen) are in the same speed range.