In my opinion, the FM2 (GM's version of the F4F - it has WEP) is a "wolf in sheeps clothing". It is a VERY DEADLY machine.
Yes it is slow at cruise speeds (not even 300 mph) and that immediately turns most people off, but it has 4 .50 cals and 1720 (860/860) rounds of ammo (my convergence is at max 500ft). It will turn on a dime and give you nice cents change, and when you point the nose down, it gains speed very fast and will bounce with the best of them. What is great, is if you miss the bounce, you then can then rely on its turning ability.
This bird has been my main ride for this tour, and I can tell you from first hand, that it WILL outturn SPITS, ZEKES, N1Ks, LA-7s and everything else that I have come up against. Once an F4F/FM2 is on your 6 with about the same e-state as you, and flown right, you WILL DIE.
I had a great fight with a SPIT Mk IX the other day. I kept doing high yo-yos as did he. Each pass we made, I gained the advantage, hardly losing any E, and completing the turn quicker than him inching closer to a guns solution. As soon as I got a decent guns solution on him, I gave him a short burst of the .50s, lit him up pretty good, turned for the next pass and when I came around to finish the job, he stalled on his turn and crashed. The pilot was an experienced Spit pilot and probably couldn't believe (like you) that this F4F was spankin' his butt.
190 natural prey ... hmmm ... the only natural prey for a 190 is a pilot/plane who is not looking/afk/focused on another target and that could be any plane in the plane-set. The 190 is a "sucker puncher".
Last night, I met up with a 190 at about 12k, who thought I was natural prey. He makes 1 up-zoom pass and 1 down-zoom pass, both misses (not hard to do against a 190). Now he decides to make a flat turn back. That was his mistake. I was gaining E on the misses and he lost E on the flat turn. 2 more turns and I was on his 6 and his precious E was ALL GONE. I throw a few rounds into him at about D550. Why he hung around that long is beyond me. Most 190s bug out after the 1st miss.
Now decides its time to dive/run, and I follow. My FM2 drops like a rock and I send a few more rounds into him as we start the drop. I am still on his 6 as we continue to dive to the canyon floor (to his amazement), so he decides to do the natural 190 defensive manuver by "stick stirrin". I'm not falling for it, just saving my ammo for the inevitable. He continues to dive further into the canyon, makes a few futile turns and eventually meets up again with the 4 .50 cals and loses a wing.
Oh ... and finally 1 of the other 5 bogies that he was winging with, finally shoots me down. All 7 of us started at approx. 12k. Not one got a good solution on me until we got to the cayon floor.