I find the window management better in OS X (kde, gnome with compiz) simply because it gives you a way to see an instant snapshot of all windows or all application windows with either a hot corner or key press. In Windows you have to mouse over the icon to get a preview that doesnt work all the time (I feel that it breaks if the window's content changes. it then shows the application's icon instead of the preview).
Mission control is somewhat nice, but it doesn't hold a candle to the very simple and time-tested method of using alt-tab. Alt-tab is ridiculously fast, works on windows instead of applications, and doesn't require you to switch to the mouse and visually search for the proper window.
Also, a new feature of Windows 7 (actually I think it first appeared in Vista) is Win-Tab. It is like alt-tab, but gives you a preview of the windows instead of their icons. If you really need to see what a window looks like while switching through your windows, that's the way to go. I don't care for it, as it's a bit laggy, but then so is Mission Control on my Macbook.
I don't find Expose or Mission Control nearly as useful as the Windows Taskbar.
Unlike OS X where a really good Taskbar implementation cannot exist, I can add something just like Expose to Windows. It's called Switcher and it does pretty much everything Expose does.
The Taskbar is still better though because it's always there and at a glance I can see what's running.
Not really; you have the option of changing how it's presented: the new style where you can hover for windows, and the old style where each window is separate, but grouped by application. Also, an active application is more visible on the taskbar than it is on the dock; it's the difference between a visually highlighted icon versus a small light a not-insignificant distance below the icon.
And, perhaps most telling, the taskbar icons don't bounce around like a 2 year-old on sugar to announce that they need your attention.
If the OS X dock were as good as the taskbar, it'd have one item per window instead of one item per app. I'd be able to put the finder icon where I want it. I'd be able to have launcher icons (quick launch) separated from items that represent running apps or windows. I'd also be able to put it at the top of the screen if I want to.
OS X is basically rigid where Windows is flexible.
