The F6F kicked ass... in the PTO. IMHO, it is impossible to truly compare statistics between the Russian front, Western Europe front, and PTO. All three were very very different types of wars.
I mean, you can have some people argue that the Finns were the best pilots. I can make a case that the USN pilots of 1942 were the best at that time. I am sure others can say the same about most of the major air forces involved at some point during the war.
Look at the Buffalo. Things that allowed it to succeed with the Finns were outclassed by the Japanese in the Pacific. The F6F outclassed the Zeke in just about everything (except low speed maneuverability), but how would it have faired in a protracted war against the German 190s and 109s? The La7 was great, but how would it have done if it had to face the high altitude bombing campaign of the US?
Great for discussion, but you will never be able to pin down what was the best fighter of WW2. What criteria you think is important may not be important to the next person. Look at me, I am not a big afficianado of the ETO (though I do read about it). I prefer the PTO to the Luftwaffe/USAAF/RAF/VVS/etc. What I think makes a fighter great is not the same as what Batz does for instance (not picking on him, but he is identifiable as someone who prefers the LW).
All together though, it is a great discussion. And yes, the F6F is the best fighter produced during WW2 (sorry, couldn't resist saying that - whether I truly feel that way is another matter, its just my favorite).