Yeah it's been a slow process for me over the last 4 years to not being able to stand Apple anymore . OS X stability issues/software bugs/forced hardware(lack of choice) have been the number one reason. The software quality of apple has seriously taken a nose dive. My iphone doesn't help the issue either, iOS is a buggy POS and the new iTunes UI is so bad I don't use it unless I have to.
Trying to get my 4k MST monitor working in OS X with hacks cause Apple software blocks it in the nvida driver. *******s...
When I go back to OS X after using Windows I am so sad, cause when it's working it's awesome. I've been a hardcore mac only user since 1995. But times have changed, it's sad, but ohh well, time to move on.
I'm not leaving Mac's anytime soon, notebook wise the MacBook Pro Retina is still amazing compared to anything else, but desktop wise, forget Apple, if you need serious hardware and choice, look elsewhere.
I'm in a very similar boat. I also became a hardcore Mac convert in 1995 with my PowerBook , and it was the best thing I've done. I can relate to all the issues you have experieced recently, it's a sad state of apple software.
I also have a 2012 rMBP and Mac mini, with zero reason to upgrade, cause apple is so far behind in hardware.
While leaving Windows for my core activities I stayed with Windows for gaming and have built machines , it's been interesting to see all the mistakes Microsoft made along the way , how they turned things around with Windows 7 and kept plugging away in the background while apple got all the glory. Come 2016, Windows 10 is rock solid on my Windows machine , with each update making to more stable , it's a really good experiece, I hate to say it, it just works.
OS X on the other hand, having moved to annual major updates is a mess of bugs and unstable compared to my windows 10 build, I cannot blame the devs, they have so much tech debt and are constantly trying to pump out gimmick features every 12 months so support iDevics on OS X .
In the last 2 years my macs have been crashing / beach balling / restarting on a regular basis..... I cannot remember the last Windows 10 crash....I think I had one, which it auto recovered from...
As Mac users , we need to accept reality, the company does not care about its computers anymore, it's about idevices, the large part of the WWDC dedicated to iMessage shows the user group they are after. Macs for "pros" died years ago. I'll use my 2012 rMBP till it dies....by they point I'm not sure OS X will be my operating OS of choice. Same thing is about to happen to my iPhone, as I will not buy a new model without a 3.5mm jack, I love my music and have lots of quality headphones .