What surprized me was how slowly the US fighters pulled away.
In most fields apart from turn they outperform the Zero (climb, speed, accel, dive, roll, guns), however I never realized how slow getting away could be. Given a better roll rate the Zeke would have been a very much more dangerous foe.
Looking at all this with all the data in hand is of course also not exactly the boots the WW2 pilots had on. They did not know about the limits of their foe. Hence the 190 shock, - the Spit riders later discovered that they could out-climb it in some alt bands, their roll rate was also being worked on, and at the debut of the Spit IX, clipped IX LF and VIII the 190's the Spits sometimes had most things in their favour.
What makes a good fighter? Lots of things I guess...