in flight sims p-51 is awful! the yak series and la series fighter are far better. p-51 was awesome at high alt but anything in med to low it was vunerable to more manurable fighters.
LA7 to be exact... in il2 that thing was a monster... but i didnt have much issue with p51 down low or med, just cant turn and turn too much... spitfire on the other hand just owns anything down low, i rarely got shot down while piloting it.