After using Linux for a few years and learning that you had to do a bit of research and buy hardware carefully to make sure it all worked, I discovered that I could choose ever so slightly more carefully and everything would work with even less effort. I use a MacBook for my main workstation and since finding Divvy and SizeUp haven't missed Linux it all.
I just want a Unix machine that I don't have to fuss over or spend time setting up and maintaining.
Weirdly, that's the reason I switched from OS X to Debian. OS X's hardware support is fine, but I do a bunch of hobby and open-source programming, wrestling with getting stuff to compile under OS X is just not my idea of a fun afternoon. MacPorts is a joke compared to the size and reliability of Debian's package archive, and Debian doesn't make you compile everything yourself, or leave multiple, uncleaned build-trees lying around for every package you install.
That's a good reason to prefer Linux. If OS X didn't have pretty stable and easy system upgrades and migrations I would miss Linux package managers. Copying the list of installed packages to a new machine and then running aptitude update is just awesome.
I have pretty moderate package manager needs so homebrew is good enough, and when homebrew doesn't have it I just install from source.
I just want a Unix machine that I don't have to fuss over or spend time setting up and maintaining.