"Apple's native operating system software offers you the best hardware support on Apple hardware, and the Mac Mini is no exception. Some of the hardware works just fine under open source systems; some isn't supported at all, or works only partially.
"This article looks at the current state of Linux and NetBSD support on the Mini. If you need all the hardware and options fully supported, these open source options won't do it for you... yet. But, if all you need is a stable kernel, a C compiler, and network support, the code is high-quality and the price is unbeatable..."