I was developer of Apple since 1989. Finally gave up when Apple ceased making any improvements. Apple had the potential for being a really, really great system. The basis of Mac OS X, is really Mach, and Apple needs to capitalize on that, but they never did. Mach allowed for concurrent OSs - the limitaion is just the hardware. In the early Apple Mac OS X beta, Mac OS 9 was in a separate window. Apple descided to scrub that - never understood why. But is theoretically possible to have multiple concurrent OSs on an Apple machine - Dos - Windows - X, BSD, OS 9 etc .. Apple never followed through. Also, Apple never followed through on important security issues. The problem with most Mac people just don't want to take the time to learn UNIX, so they remain ignorant as to the vulnerabilities of their system.
Whether you believe me or not, I don't care. Whether you believe that UNIX has vulnerabilities, I don't care.
I think this ostrich syndrom is probably why Apple is only at 3% of the market, and Linux is overtaking Apple in many areas. (Law of unintended consequences: Linux was born to take on Windows, and so many of the smaller companies and competitors have been out paced by Linux.)
I'm not a fan of any system - just a realist. And when a Mac person tries to claim that they are immune, I just laugh.