IIRC the ranking was F6F, Fw190D-9 and Spit XIV with P-51D ranked fourth.
I had a long running debate with Captain Brown (via letter) because I felt that he undervalued excellent performance combined with exceptional range, creating a special niche for ranking fighters.
He concluded the points I made about strategic footprint was valid, but his ranking was solely about his views regarding performance and agility... and we then launched into P-51B vs Fw 190D-9 and he fell back on firepower, so then we launched into air superiority (P-51B) versus wide range of destructive capability (favors D-9)...and then as an extension of new versions based on cycles (Fw 190D reached operational units in late November 1944 vs P-51D in May, 1944 versus P-51H in April 1945 and Ta 152 in ~ February/March?) and we went round and round again.
BTW he is an Aero Engineer in addition to being a reknowned pilot. I may disagree but I concede his unquestioned qualifications to pontificate.
Over the many years, I have not had an opportunity to talk with Brown, and I was never really keen to bother. I have spoken to many WWII era pilots who involved in flight testing, with Corky Meyer being among the most objective. Brown and Meyer have butted heads many times. Brown's edge was being an actual combat pilot (albeit, limited), and Meyer's advantage was being a top tier developmental test pilot. Corky argued that the F4U-4 was utterly superior to the Fw 190D as an air to air fighter. You would think that he would have argued for a Grumman fighter, and he did point out that the F7F Tigercat and F8F Bearcat were even better than the F4U-4, but since neither had an opportunity to get into combat, he limited his choice to the Vought. Corky was also a vocal advocate for the P-47, especially late models. Corky believed that the P-47 was without peer at high altitude and did more to crush the core cadre of the Luftwaffe than any other fighter. I agree with this view.
At one time or another, Meyer flew everything in the US inventory, as well as Brit and captured German fighters. Corky was a graduate of MIT. He would eventually become President and CEO of Grumman.
Sadly, Corky passed away less than two weeks ago. A major loss for the aviation community. A big

to Corwin Meyer, a giant in American aviation.