Slash27 and I stooged around with the Boston vs P-38s and Ki-84 a while back.
He can testify that the Boston is remarkable for its size and weight. A good stick will whoop up on the unsuspecting. No one expects the Boston to engage in a dogfight, much less a stall fight. Thus, it can surprise the unwary. It has some serious weaknesses, but the average MA player won't know what those are, other than the weak battery of four .303 MGs up front.
My regards,
Widewing