A couple more comments on the issue of Unix and Macs:
Most people using Macs will never know there is “Unix” lurking behind the nice GUI. Never. They have no clue, want to have no clue. They want a computer to “just work.” And for the vast majority of Mac users, the Mac does just that: “Just work.”
With no other edition or version of Unix has this been possible, and I say this as a guy who has been around Unix since, oh, BSD 4.2 on VAXen and V7 on PDP-11’s. Yea, I’m dating myself. I actually liked V7. It was clean, small and handy. Back in those days, I got a lot of work done with either RT-11 or V7 on PDP-11’s.
The various desktop Unices on PeeCee hardware are trying... they’re trying so very hard to be seamless and glossy Windows replacement machines... but they have not pulled it off. They might yet in the future, and some editions of Linux are getting closer, but they’ve not closed the deal yet.
Now, as a Unix system goes, OS X is wonderful. I happen to know Unix, have spent the majority of my computing career using one version/edition of Unix or another, and out of all of them, there are only two that I’d put up with for a week: Solaris 2.5 or later, or OS X. The rest... they all have their problems and rough edges.
The nicest thing about OS X is that when I flip open a ‘terminal’ window, I can get bash by default, and I get a bash-on-BSD experience, which any true Unix hacker prefers over SysV. I don’t really care about the microkernel issues, or whether something down against the hardware is Mach or BeOS or BSD. I’ll care about that if and when I write a driver... which won’t likely be anytime soon, because I’ve moved on to doing other things with computers in the last few years. However, for picking up some FSF/GNU/etc open-source software and either porting or compiling it up... OS X is a breeze of a target to hack to. Pud easy. A heck of a lot easier than porting GNU/FSF software to SysV was in the early days, lemme tell you.
And when I want to quit dealing with Unix... I just close up the terminal window and go back to “just using” my machine as an ignorant user. I have no need to open a terminal window except when I want to play Unix hacker again. And when I want to have a foot in each word, I have tools like AquaEmacs: All of the Unix-geek power of Emacs, with a pretty Cocoa GUI. Sweet.
Actually, I have found a need to do that. The OS X GUI has very simple and effective power management, in fact I loved the UPS automatically being a part of it when I plugged it in, instead of having to install drivers and programs. But what's underneath is much more configurable. I wanted to do some power management a bit more fine-grained, so I had to drop to Terminal and use pmset.