I've used, mainly for development purposes, all major operating system of today (Windows, Linux and Mac). I have to say that any of them can be used for doing your work.<p>You can have a Unix like environment on Windows or on Apple, and you can have nice GUIs on Linux.<p>The debate is basically based on ones tastes. But you can not say that Microsoft is irrelevant, it could be of no use to you personally, but in the end if you work on software development it will matter.<p>I can agree with you that Windows Phone 7 is a disaster, but Office 2010, Windows 7 are success stories.