This. I switched to OS X from Ubuntu about a few months ago simply because of this reason. I was too tired of tinkering and configuring endless .conf files, adjusting my GNOME/Xfce panel layouts for optimum productivity, and changing my display manager because all of them sucked.
In my final days with Linux I was running Ubuntu Minimal with twm -- I went completely old-school. Fewer things at the core, fewer things to go wrong.
I caved and bought a MacBook Air. While I miss the endless configurability of Linux, I find that most of the time I spend trying to configure OS X is only spent to make things more suitable for my workflow -- changing the number of desktops I have, changing the applications in my dock, or adjusting Exposé to show all app windows.
I never have to configure something because it breaks or isn't compatible with something else. I could have gone the FreeBSD way, but then, well, you know. OS X just works. As a Ruby and Java developer I find it perfect. I probably will try the 13.04 release on the Mac (I tried the beta and liked it), and I'll see how it goes.
It looks like a solid release, so I'd really like to keep it (but I probably won't because I'm cheap and only have the 120gig SSD).