pfffft bloody linux users, soon you will be saying you changed to osx
Fuck no. It uses a FreeBSD kernel - which has always been my preferred server OS. Far more secure, stable and streamlined than Linux distros. A lot of Linux guys are put off it because it has some quirks that confuse them (unless they're old blokes that actually used UNIX). The BSD flavours are very serious about security, and are very good at not wasting resources.
I won't use OSX as a Desktop OS though - too limited to hardware choices, and it really has this market at not letting you screw up, which is really, really, really frigging annoying when I know exactly what I want it to do lol.