Not surprisingly, the P-51D had the most kills with 13,903. What does surprise me a bit is the 190-D9(6672), La7 (6663), and P-47M (4287). Similar role planes, each one superior to the PonyD in several respects, yet far less usage.
Second in sheer number of kills was the SpitfireXVI, with 7050. The two other important spits in the MA, the VIII and the IX added 2241 and 2204 kills respectively, bringing the total for the 3 significant Spits up to 11,495. The XVI had the highest k/d, at 1.21, followed by the IX at 1.07. The VIII lagged at third with .98. I guess roll rate really is important.