I can only speak for myself here. Having been a Windows administrator for nearly 20 years and a Linux admin for around 10, I switched my small business from Windows to Linux several years ago.
My experience has been that, in our applications, Linux takes much less looking after than Windows and we get to spend more time doing things that make us money. In addition, there's no need to spend money on anti-virus products. We now use one OS across all our desktops and data centre servers. I even have Linux on my mother's home PC and she gets on fine with it.
The largest thorns in our side are the closed source programs we deploy: The binary nVidia drivers and Flash are implicated in over 90% of desktop crashes we experience. We consider the nVidia driver to be one of the most unreliable pieces of software we have and it's been our experience that it tends to fail under heavy load, particularly if Flash is in use. I don't remember the last time one of our ATI desktops crashed. Unfortunately, my main machine is a desktop-replacement and doesn't have a removable GPU otherwise that nVidia card would have come out a long time ago. We now consider "nVidia inside" as a negative when making purchase decisions.
I do care about the about the freedom of the source, not from an ideological point of view but because I think it makes better sense to work with software which lets me contact the developers, look at it myself or pay someone else to than with programs that are closed and I am at the mercy of a development team. As I said, we are a small business, yet I've had many productive interactions with the developers of the software we use that have made a positive difference to us. In contrast, my largest customer has tens of thousands of Windows licenses and even they can't get hold of the team that developed the code or feed in change requests.
We do have one Windows machine left (a dual boot with Linux) for dealing with firmware updaters for some of our customer hardware. This machine was recently updated to Windows 7 and, in my opinion, 7 is the best desktop version of Windows to date. However, the Linux desktop experience is now so good that we're not tempted to switch back at this time. I'm not saying that Linux is the right choice for everyone but I still believe it was, and still is, the right one for us.