Mac users seem incapable of distinguishing between a bad format and a bad port. Flash on OS X is the latter; Flash runs about the same on my 2.16GHz C2D MBP as it does on my 1.6GHz Atom netbook. I don't run around foaming at the mouth about how irredeemably bad Flash is, though.
I would go so far to say it's a bad format AND a bad port. It's not an either-or situation. Just because Flash sucks less on Windows doesn't mean it's a good format.