I used Linux for years. I built a MythTV box and bought a digital TV tuner card for it and, later, a device to get the video from the cable box, along with an IR blaster to change the channels on the cable box. I have owned five laptops on which I used Linux exclusively (1 Dell Latitude, 1 HP EliteBook, and 3 Thinkpads). I built my desktop system for Linux. I have used Debian, Slackware, Ubuntu, Arch, Gentoo, and SUSE as my daily drivers, and have tried other systems like Mandriva and Fedora. I have compiled kernels and filed bugreports.
I now use OS X. In the end I got tired of desktops with tons of broken stuff. The transition away from GNOME 2 and KDE 3 was rough, with years of no usable major desktops at all. So I switched to barebones window managers like i3, FVWM, and Xmonad. (I have XMonad to thank for introducing me to Haskell, which I still use daily.) I got tired of reading man pages to do simple stuff like change my clock.
The thing that broke me in the end was doing my US income taxes. Our taxes are complicated so it helps to have software to do them. There's nothing for Linux. So I filled in my taxes on PDF forms. Even that was not easy: not all Linux PDF readers have the ability to do forms, and figuring out which ones do requires forum searching or trial-and-error. So I resorted to Adobe's non-free software. Even then, doing a US tax return on fillable PDFs is awful. I considered using an online service but I did not want a cloud solution for my private data.
That pushed me over and I got a Mac. I had actually tried Macs a few years ago when they were making the white plastic Macbook, but I returned it and stuck with Linux. I found that OS X had come a long way since I had last tried it. I enjoyed doing little things like downloading a song--things that would be a pain on Linux (do I have the right codecs installed? the right package?) And there's a ton of third-party software available. Some of it costs a few bucks, where something similar on Linux would be free--like a little tool to graphically show what is eating my disk space. But it's worth spending a few bucks to save hours hunting for something on Linux and fixing the breakage.
So that's why I don't use Linux. My time and my ability to get things done is more important than nebulous "freedom". Proprietary software provides an incentive to some companies to produce useful software. So be it.