
Well, now the truth is out. In a nutshell, Flash is more efficient in Windows than HTML5 because it can access the video card's hardware acceleration. But on the Mac platform, Flash is signficantly slower because Apple won't let them use the APIs!
This information kind of throws a wrench in Apple's circular argument. Apple won't loosen control of their hardware to allow Flash on the iPhone because Apple says it is a resource hog on the Mac, because Apple won't let Adobe make it more efficient, because Apple won't loosen their control over their hardware.
I think it's time for Apple to let Adobe fix Flash on the Mac platform. It's what their customers want!