That says a lot more of how it is used than its performance. Brewsters (the ones I see anyway) are mostly used in base defense at 0 alt. No plane will get any impressive statistics from such usage that places it nearly the entire time in defensive flying. The Zekes are used a lot from carriers on offence which improves their chances of survival and getting kills.
I observe the Brew being used in very similar situations the Spit 16 or La-7 are being found (and formerly the Hurri II had been), short range defensive work and 'furballing'.
Of course, unlike those two the Brewster pilot has to build up his energy first by climbing, compared to those two (but also other planes like the A6M) it's level acceleration and climb rate leaves a lot to be desired.
I also don't find it that much different from for example the F4F, which is very capable a dive and also can stay quite well on an enemy's tail long enough for a kill. But my experience in both is rather limited (I actually prefer the I-16 a lot over the Brew).
I think the main reason for a lot of the clearly exaggerated statements about the AH Brewster is the difference of players expectations based on the reputation of the 'Brewster' (based on very little actual knowledge) and it's thus 'surprising' AH performance.
And this is what was similar when the Sherman VC was introduced. Players by large only knew from countless TV shows that "the Sherman" sucked and that it "took 5 Shermans to kill a Tiger with only one returning". I remember very well it was almost impossible to make people understand that ours a different Sherman with a British high velocity anti tank gun on par with the Panther's 75mm.
Is there anyone who knows a very successful Brewster pilot in our game who you can Q&A in this post? Might be interesting to hear from the Brewster side what those pilots perceive. Aspen has a very good point in his observation about E and ignoring the Brewster to his detriment. I used to get caught by that also. Though it could simply be we are getting a reality check on how slow we are really going versus how the Brewster started it's path toward us
I tested the energy holding capabilities in level flight (which are abysmal). A similar test could be made about holding E in a turn, though I would prefer someone else than me conducting such a test who's able to fly more precisely than I am.
My guess is that here it also isn't much better than similar planes, but controlled beats perception & guesswork