I ran Ubuntu with gnome after Unity came out, tried Linux Mint, LMDE, pure Debian, then back to pure Ubuntu with Unity. Nothing worked as well in 2013 on my several year old laptop as it had several years before, when I first got it - sluggish, slower, "crufty" feel.
When it came time to upgrade hardware, nothing rivaled the Air in terms of weight, capabilities, "feel".
I thought it would take me longer to feel "at home" on OSX, since I'd been a UNIX guy for ages, and was quite comfortable with XP, Win7, and, of course, Linux.
But it took minutes. Many, many "oh wow" moments. Right now, I am 3-fingering back and forth between FF full screen as I write this and FF streaming a bowl game. Gestures are the bomb.
Getting Linux to the point where it "just works" like my Mac just works takes time. My Mac "just works" out of the box. The longest thing it took me to figure out was how to get tab completion to ignore case.
And that's another thing: The OSX community is more up to date and more consistent on their platform than the Linux community. And they're more polite.
Google the same thing on both platforms. Under Linux, you'll find many old and badly wrong answers and many more "I think it's this" written by people who barely understand the question and haven't bothered to test their hypothesis. More recent answers will generally be worse, sadly. And there will be much snark. Much much much.
The answers from OSX users will be fresher and more consistent. It used to take me hours to wade through all of the Linux resources to figure out where the quality lay.
It takes minutes on OSX - the community is simply better and more consistently informed, and more polite and more helpful.
EDIT: Bear in mind that "the user experience" includes the hardware. This beast is just that - a beast, and a very light one at that. I never get the impression that I'm going to break my machine or that it will respond oddly. Overall, the OSX GUI plus UNIX under the covers with all the CLI I love plus the Air HW is an awesome UX.