the comparisons of aircraft on this site are always enlightening and very interesting. I can add little.
The test evaluators at Wright-Pat considered the Yak 9 superior to the P 51.
The French pilots that flew the Spitfire, P 51 and the Yak 9 preferred the Yak. I don't know which models of Spit and Mustang.
I would say the Yak-9U with the Klimov 107 engine. The usual Yak-9 withe a Klimov 105 was to short, in performance matters.
No Spit or Mustang were proposed to french pilots at Ivanovo in 1942-43. Only Hurricanes or P-39's and Yak-1.
For sure the best aerobatic warbird in 45-46 years was the
Normandie's Yak-3, beating even
Ile de France's Spitfires IX and XVI on that point. Since very impressive in airshows, it was less appreciated than the sturdy and well protected La-7 in realfights by soviet pilots. French pilots asked for Lavotchkins for many and many times, with no result.
I would add that Marcel Albert, the secund french ace
is (not
was, because he's still alive) not impressed neither from the Messerschmitt 109, neither from the FW-190A-8 flying qualities that he had tested in the STAé once the war ended. After -
the "violent" Yak-3 reactions to commands, they feel heavy ans sluggish", viewed from the cockpit- he said, to a french virtual pilot's club.
The" French" Mustang reached about 680 km/h from MAE datas. It's less than usual admitted numbers, but it was a serial aircraft with probably some wearing. Anyway
all the american planes were much better manufactured than european one's. It's why they are much appreciated by collectors. And BTW very much closer to their theoretical performance numbers than the others. At the end of the war it was noticed a great fall of production quality of german planes both from french (allied?) and soviet accounts, and from german vet's that spoke to Jean Salis at la Ferte Alais center. It should be not ignored either.
But regardless the Yak, La and Spit ability to outfight the Mustang on a dogfight, they were not able to protect strategic bombers or catch Me-262's deep inside the Reich territory.
So
yes, it was the right plane on the right place for allies!
Regards