The Only Two Reasons M$ Loses my Business
Stability and Anal Retentiveness.
I initially axed windows from my home PC about a year ago because I was tired of hearing my friends talk about how much more stable Linux was than my Windows. The crucial blow to my windows 95 OS was the random crashing. It started when I downloaded the demo version of IE 4.?? and it was only in Beta stages. Every so often, my machine would lock up completely.
So my friends convinced me to change my ways. They donated a small (2.4GB) hard drive to my cause and installed RedHat 5.2 on it. They taught me the basics, and left the rest up to me (although I did have 24/7 "tech support" with irc). Playing around with it, I liked how it's possible to truly test a program before relying on it. Which brings me to the next reason.
With M$, to buy something is to commit yourself to it. If the product doesn't meet expectations, it's virtually impossible to return it, and extremely impossible to fix. All you have the ability to do is submit a whine to m$.com. With the GPL, downloading and checking something out first is easy. And there's always another program that you can try if the first one didn't float your boat.
Bottom line: Linux is more convenient.