I too was very sceptical when I got mine. I' ll never go back now, never. I can say without question I' ve harvested several deer that would have been almost impossible with my old fork-ed one.
As for speed, I shot a group of three arrows with feathers and with vains both at 20 yards. The vains were 2" lower. Even if you shoot vains I still believe it' s the rest to have.