Just had an interessting 1vs1 in a Brew vs a F4U-4. I had more alt on him at the beginning so i could dive on him and get on his 6. He pulled up in a rope and i followed him up, roughly the same speed initialy. He ended up about 600 yards above me but i got enough hits on him to hurt him bad. A top ace would prob have came down and killed me but on the other hand it showed that not even a U-4 is safe against a Brewster in a rope if they have the same speed to start with, The U-4 will get about 2000ft higher but that migh not be enough to prevent the Brewster from landing hits on u.
If its done over time im sure the -U4 will end up as a winner far more often than the Brew but the U-4 is not invincible and will get shot down sometimes.