Fortunately, there's plenty of interesting people using Mac OS X. One of the pretty interesting reviews I have recently discovered (if it is old, forgive me) is Amit Singh's "What is Mac OS X?" article. Quoting first paragraph:

This document attempts to give a hacker over-friendly answer to the question "What is Mac OS X?". My original motivation in writing this was that somebody had proxy-volunteered me to give a talk introducing Mac OS X to the Linux Users Group at my work place. While thinking over what to say to those folks, most (if not all) of whom are strangers to Mac OS X, I decided to write a supplementary document that they could refer to at their leisure.

An interesting read, even for me. Thanks, Amit!