I'm going to get a lot of hate for this but if you really, honestly want a no-frills, easy to set up UNIX for your personal computer, there really is no better machine than a Macintosh.
At home I have a collection of misfit laptops that were discarded by others or sold very cheaply. It is these laptops on which I tend to run a Linux distro (because Windows tends to be slow and no SSH; because I'm not really in the business of Hackintoshing.)
Running eOS Freya on one of them now. It's not bad. Wifi seems a bit temperamental--which is astounding given that eOS is based on Ubuntu and Ubuntu had no trouble with wifi.
That's why I said personal computer :) Another OS X pitfall is that modern, vendor-supported versions are somewhat resource-intensive and not very fit for running on older or less powerful systems.