Have to disagree somewhat. One of the biggest grievances for me as mousesuperhero (I hate using keyboard :|) is that I find most windows managers (mostly kde/gnome/compiz) with intel or nvidia GPUs tiny winy slower on screen rendering compared to Windows (flickering, redrawing, tearing etc.). Then again mostly on my system linux beats hell out of win on networking and disk IO. For some reason I still manage to make my win system almost complete halt with just simple dvd-drive recognization or network drive that is unreachable.

But on graphic side and responsiveness (how long it takes to menu popup when you point/click it with mouse, small differences make using menus to me unbearable) I hope that Wayland manages to help on some speed issues which might seem to be irrelevant to x-term warriors

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And for some reason I think that making GUI fast as possible and then faster could be the most important thing to do when you start marketing stuff to Average Users. We are not talking about seconds but milliseconds that matter. Btw. From wiki citation:
http://www.youtube.com/watch?v=YRYTCQqrFcA