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.
To people inexperienced building V-tails, they can be intimidating and a little bit of a learning process. I'm sure the speed of each would be very close and neglibly noticeable to just about everyone.
I think they just look cool
Well, yeah they do look cool. And I agree that they are foreign to some fliers.. and that counts for a lot. I would say that unless the V-tail option is nearly perfectly refined, the differences are small enough - if even tangible - that it may be more important for a pilot/racer to go with the style that they know and trust, so that there is no mental factor distracting their focus.
Like elliptical wings or many high performance airfoils at lower Rn, the theoretical advantages are destined to remain theoretical if they are not executed with a certain minimum level of precision. A narrow chord section near the tip of an elliptical wing that, under a magnifying glass, looks like the cross-section of a rough-hewn timber, is not good for much for example. But I would say it is easier to construct to the level required to realize the advantages of a V-tail than perhaps those of the two examples just mentioned.
Positive factors for V-tails - fewer fuselage junctions, and two sets of tip losses instead of three.
MJD