I've used DOS, Windows (3.1 thru XP), Linux (KDE 2.2 and 3.4.1) and Macs (System 7.1 through X 10.2.8, which is what I'm using now), and I keep coming back to the Mac. I'm more comfortable with it, and having used Linux makes it easier to live in a BSD-based OS X world.
Admittedly, this time it has taken me longer to switch from Linux to the Mac (a week) vs switching from Win 2000 to Linux (a few hours), but then Linux is geared to switch from Windows, and not to the Mac. That just makes sense, given market share.
I'm running 10.2.8 and version-matching software to this older System took the longest time to switch and tune (porting my maildir-based mail store to mbox took the next-longest), but I'm done now. Like others before me in this post, I am learning with the Mac to quit tweaking incessantly and just use the machine to get things done. It's restful, in a way.
Having the guts of the system mostly inaccessible to "normal" people, as BSD and Linux do, really helps in that regard. The way the OS X Mac writes its config files in XML, instead of plain-text is even better for the normal user over Linux. Even better, developers can still access config files to modify them.
I can consider myself a power normal user, and that's all. I don't know how to program nor script, so I'm not a power user. But I do tweak, and have broken stuff. Mightily. Especially with Windows, any flavor.
Why? I *hate* the Registry. I just can't keep it clean. "He tasks me, Joachin, and I will have him." I know where to look, and I've learned what to stay away from - I hate needing to clean it all the time! I don't care which version of Windows you have, the Registry architecture and sheer concept of it is fundamentally broken. I also hate the pop-up windoids in XP; they slow me down massively.
It's easier to deinstall applications in the Mac (drag to the trash, and hunt for old preference files every month) and it is easy for Linux, too, with package managers. You *cannot* deinstall programs in Windows, not completely; there's ALWAYS Registry entries left over, at least.
I know that you can do *lots* with the Terminal, and I have learned to do some some stuff, but I don't think I want to be a maven (Yiddish: an expert) at it.
Mac vs Windows, no Real Difference?