Others are certainly more qualified than me to answer, but here's one person's opinion anyway.My understanding of the conventional wisdom is that a Pitts or Eagle is capable of flying anything up through Advanced (one level below the Unlimited flying you'll see at the WAC). However, the monoplanes are said to "show better", owing to their longer wingspan, clean lines, crisp response, higher roll rate, and often higher vertical lines. My impression is that, given equally-skilled pilots, the high-performance monoplane (Edge, Extra, Sukhoi, etc.) will outscore a Pitts or Eagle.
That said, I also think the pilot, rather than the airplane, is the limiting factor in the performance of most pilots. Once you get to the S-1S/T and S-2B level of Pitts, I think there are not too many pilots who are better than their airplanes.
Tom P.