Anyone who either owns both or has owned both that could give their experience with the lens performance comparing the 200-400vr with either 400mm prime or 500mm prime lenses. I was pretty settled on getting the 400 or 500mm prime, someone suggested I look a bit at the 200-400mm lens. I seem to recall a discussion where several people commented on how much slower tracking or obtaining focus was with the 200-400mm compared to either prime. Also, If I were to go with the 200-400mm it can only be assumed it would get worse with a TC than either prime both on sharpness and on tracking/focusing. The other side of that is having the ability to zoom in and out helps in composing shots, at least gives a lot more flexibility without moving your feet. Appreciate any input from owners.