Well I'm back on a Macintosh, in the sense that it's again my main platform for futzing with my personal data. I broke away a few years ago for some of the following reasons:
*economics and computers at home
*less-than-favorable opinion of Apple's choice of "Walled Garden" software ecosystem
*need to tinker
*optimizing performance
*what I moved to:
Puppy Linux (a.k.a. Try running THIS in ram on an old Pentium!)
Debian/Ubuntu on AWS (a.k.a. Look, no hands on the server!)
the BSDs (a.k.a. FreeBSD is bulletproof, and I can put NetBSD on my toaster!)
And why I returned to the Mac:
*need to Get Stuff Done
*sharing computing resources with Family, all who need to Get Stuff Done
When it comes to doing SysAdmin stuff on a "non-Mac", it's exhausting trying to track system State only in my head. Even with "screen/tmux" helping out for command-line stuff. Also, it's a well-known fact, that it doesn't take much for Family to wipe out whatever you're trying to maintain in your head.
Actually, I had been using a (fairly) modern MacBook since Summer '12, but a major turning point was Spring '13, when I wiped that box and did a clean install of "Snow Leopard" (10.6) onto a SSD. I had the ambitious plan to document every step of the whole project, but naturally I got more focused on carefully doing the steps--each with a CMD-Z "undo" contingency--rather than setting aside time to write down what those steps were.
Why did I choose SL, which by then was already two major releases obsolete? Well, in general, I had the benefit of 2 years of hindsight, after which everyone realized just how good SL really turned out to be. [Update: Here's a discussion of Snow Leopard relative to "Yosemite" (10.10).] And long-term stability is what I learned to re-appreciate, after having to figure everything out while I was living in the Linux distros. Sure, even though I had been running Debian Stable, Ubuntu Long Term Support, or Mint-derivatives of either, I missed being able to have things just work, and overall just get things done.
After Apple and everyone stops supporting Snow Leopard, only then will I check out the Lions or Mavericks or whatever else comes after. And again I'll move if history/hindsight reveals one of them to similarly be another long-term winner (best case)...or if I can figure out the least-problematic version to settle for (worst case).