I really don't think the Spit 14 deserves to be perked either, actually. Of course, this is coming from a "LW-centric" point of view... I look at the Spit 14 and I see performance that is similar to the G-10, but with better guns. But the G-10 is a little faster down low, where it counts, so it kind of evens out in my opinion.
Sure, the Spit 14 is a "monster", but so is the G-10, and the La-7 (which is better than both, again in my opinion).
The F4U-4 I don't really have much of an opinion on, I hardly ever fought one or flew one.