ORIGINAL: daven
Your right, very minimal. The largest arguement I hear in favor of the V-tail is that their is less junctions between the tail and the fuse, hence less drag.
... I'm sure the speed of each would be very close and neglibly noticeable to just about everyone.
I think they just look cool
It seems you would have less drag going straight but more in turns. Heavy up elevator would also be like applying left and right rudder at the same time. But they do look cool.