Well, here's a comment about B-239, it was said by Ilmari Juutilainen, leading finnish ace (97.5 victories) : "I started my Brewster flights in the beginning of April 1940, doing all the aerobatics maneuvers, stall and dive tests. I was happy with my Brewster. It was agile, it had 4,5 hours endurance, good weaponry - one 7,62 mm and three 12,7 machine guns - and an armored pilot's seat. It was so much better than the Fokker that it was in another category. If we had had Brewsters during the Winter War, the Russians would have been unable to fly over Finland."
So, remember that Finnish Brewsters were F2A-1 models, which was much lighter and more agile than later F2A-2's
I'm still not saying it was the best fighter, but pretty good in the circumstances