"Respectfully disagreeing, JAB, the H model never saw, therefore, proven itself, in combat, and was never even produced after 1946. Several models of Corsairs and P-51D's was used as late as 1978. "
You can consider the P-51D and F4U-4 contemporary aircraft in that perspective, but in an aircraft comparison is it really "fair" to compare a new model of plane X to an older model of plane Y? This sort of comparison serves only a single purpose--to "prove" the writer's point--in this case, to "prove" the F4U-4 is so superior.
If I wanted to, I could "prove" the P-51 is better than the Corsair, by comparing a P-51H to an F4U-1D. Would it really prove anything? Of course not!
From a design evolution standpoint, the P-51's and F4U's match up pretty well. You have the P-51A and the F4U-1, both the initial model with certain glaring problems (P-51 sucked up high, F4U had lousy handling); the P-51B and F4U-1A as the initial revision; the P-51D and F4U-1D which both had their multi-role abilities improved at a slight cost of performance, and the P-51H and F4U-4/5, the utimate versions of each design. In comparisons between those airplanes, none is ever really "better" than its counterpart.
In the end though, I still maintain that ANY comparison between aircraft is pointless without also accounting for the job required.
J_A_B