Linux is a superb server OS. On the desktop... well, it depends.
When Win98 was Microsoft's current OS, I used Linux as my primary desktop OS because it was stable and did what I needed it to do. I wasn't a Linux zealot or an anti-Microsoft crusader. I just wanted a stable OS that didn't lock up or crash several times a week. So I used Linux for most of my day-to-day work, and Windows for applications that wouldn't run on Linux. I always preferred the Debian-based Linux releases for the desktop.
After Win7 came out, however, I gradually found myself spending more and more time in Windows; and now I spend almost all my desktop time in Win7 or Win8. (I still use CentOS for my servers.)
That being said, Linux Mint is a very capable desktop Linux distribution. I use it mainly for resource-intensive tasks like video transcoding because it's fast and resource-efficient. I'm also toying with the idea of building a media server on top of Mint for the same reasons. But I could happily use Mint as a desktop OS if not for all the Adobe software I run.
Most of that software (Dreamweaver, Fireworks, Photoshop, Premiere Pro, etc.) cannot be made to run properly on Linux. I've gotten some of the programs to run poorly on Linux in the past, but never well enough for production use.
But it's all moot now. Microsoft has finally figured out how to build a fundamentally excellent, stable operating system. Two of them in a row, in fact. So I no longer mind spending my days in Windows.
-Rich