I have to add that it's because of the manner in which each OS deals with the hardware layer that many of us prefer Linux or Mac over Windows. It's not (just) the perceived elitism, it's not that we enjoy having fewer apps and interoperability issues with Windows, it's not because we're just hate Windows for no reason. Linux and Mac control the hardware layer in a far superior manner to the way Windows does. That's the reason Mac's aren't considered "upgradeable" to the extent a PC is. Mac and Linux are tied closely to the hardware. They access the hardware more efficiently than Windows, thus there are far fewer system freezes or crashes.
Everyone appreciates an attractive desktop, but the true test of a computer is at the hardware level. The better the windowing system works together with the software and hardware, the better overall performance the user sees. A stable system allows the user to accomplish their tasks without having to think about what all is going on inside the magic beige box. An unstable system, like Windows, drives its users nuts by interrupting their work with freezes and demands to reboot (something only done in other OSs for changes in hardware) because the processes confuse the processor.
I also like the way the file system works in Linux better than the one in Windows (I'm still slightly confused by Mac's file system). And software generally installs better, more logically, in Linux and Mac.
No system is perfect though some are less perfect than others.
