When you're talking about the Spitfire non-AI FM you're definitely right. The Spit is capable to climb vertically with the 109, no overheating, 3 hits from 1km bellow in the 109's wing are enough to seize the engine, it easily follows the Dora in the shallow left turn climb.. and so on..
The AI is.. well, I don't play against it as it's a mood killer, at least to say..