I've also grown tired of the need to find a new distro every 18 months to two years when the one I happen to have been using for a while decides to embrace batshit crazy as its new philosophy. I've used most of the major distros in my time except Red Hat/Fedora. My last distro was Debian after Ubuntu ruined everything with Unity, but even Debian with GNOME 2.3x wasn't doing it for me any more. My new PC hardware also seemed to have some stability issues so I just decided to jump ship. Another consideration was a decision to write software for Mac/iOS to make money. Nobody makes money writing software for Linux (not easily, anyway), and Apple has a loyal customer base used to not being afraid to spend money on good/useful software.
I have to say that Time Machine is great, and transferring a user account/profile from one Mac OS install to another is dead simple. Microsoft could learn a thing or two about how Apple does this (the User State Migration Tool for desktop admins is utter rubbish by comparison). Switching to Mac was made easier knowing that it's fundamentally UNIX underneath, so I have the best of both worlds. A rich ecosystem on the desktop where batshit crazy isn't foisted on its users willy nilly and a foundation that's rock solid. What more could I ask for? And most of my favourite OSS software is available on Mac, anyway, like Open Office and The GIMP. No brainer, really.