Agree, there are clearly a lot of fan boy responses. I think Microsoft Windows is a pretty great OS, It's not Windows fault there are so many noobs who don't know how to use it.. =/
Anyway without Windows we wouldn't be so far, PC's & Microsoft are always a step ahead in terms of hardware & new technologies, there is support for DirectX 11, OpenGL 4.0, Crossfire & SLI (dual & quad gpu) technologies, even hybrid crossfire which means you can mismatch video cards.. Just recently AMD announced APU's, which is an accelerated processing unit.. And well Apple has none of the above, they don't even have support for OpenGL 4.0 yet..
With Mac OS there is no scaling when using dual GPU.. you can only hook up multiple monitors, thats nothing =/.. Where as on the Windows side you can hook multiple graphics cards and typically get double the performance.. and not only that you can hook up to 12 displays..