What about the F4U-4 (and later versions) and the F8F Bearcat? 
Both were a match for any land based fighters. How about later Seafires too? Yeah, there was a brief gap in terms of early jet fighters, but that gap was closed rather quickly as more powerful engines became available and the Navy's belated acceptance of swept-wings for carrier aircraft (their primary concerns being takeoff and landing speeds and handling, plus the rather slow spool-up speed of early turbojets, even worse for centrifigal flow designs, being a factor) allowed for greater performance beginning with the Grumman F9F-6 Cougar and North American FJ-2 Fury. Oddly enough, the F9F-6 proved to have better low speed handling qualities than the straight-wing F9F-5 Panther.  -Widewing
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You are absolutely right and it's certainly open to debate.  What I stated about parity not being achieved until the F8U Crusader was just my opinion.  I'd have to look into what are true contemporaries of the F4U-4 and F8F (which I would guess include everything, prop or not.)  I'd love to have access to a Bearcat in the MA!   
