window management is indeed better designed on windows (since 7) which makes your parent poster's claim a bit unsubstantiated, but thinking about it a little more there is something to it: Windows applications, especially since the ribbon UI pattern has emerged, are often specifically designed such that you need them to run in fullscreen. Try using office on 950px width and you know what I mean - you simply can't get to lots of control elements comfortably without the full screen width. Mac software on the other hand has always been optimized for multiple non modal panels, still carried over in the prominent info window even in consumer apps. You can place that thing wherever you want. For power users this is very good because they can position these windows as close as possible to the content they want to edit, scroll the window behind without loosing focus (still not a standard windows feature) and do a series of operations minimizing mouse movement and clicks, since a panel of similar operations as their last one stays open. This as well as the always accessible main menu is what allows users to play around width the width of windows.

If only window management and multi screen support were as good as the one on windows - it would pretty much be a perfect classic desktop environment.