I agree.James Steele wrote:it seems like Apple is leaving us behind.
The tipping point for me is hardware. I haven't had major software problems for a while now, though I am concerned about frequent macOS updates causing compatibility problems.
I don't know what the El Capitan problems are that he mentions in the article, but I recently installed it on my 2009 MacPro and so far everything seems fine. (My main music apps are the latest versions of ProTools, DP, and Sibelius.) My laptop runs Sierra, and it seems fine.
I don't need to update either of my machines just yet, but if I needed to right now, I'd seriously consider switching to Windows because none of these options seem very good:
2016 MacBook Pro: IMO, removing physical Escape and Function keys, SD slot, Ethernet port, and standard USB ports is absurd; RAM is still limited to 16GB; and the price went up.
Mac Pro: aging; was too expensive for me when released; I preferred the tower form factor (I have five drives in my cheese grater)
Mac Mini: seemed promising as a music computer, but I suspect Apple realized that making it too powerful would poach sales from their other lines. In any case, it's overdue for a refresh; RAM isn't user-upgradeable and capacity is limited to 16GB; and the latest version's CPU went from 4 to 2 cores.
That leaves the iMac. I've always preferred to have a separate display and CPU, so I'd be hesitant. I seem to recall people mentioning fan noise.
As for the latest OS features, I couldn't care less about Siri on the Mac; I won't allow Apple's cloud services anywhere near my Documents folder (Sierra tries to get you to sync Desktop and Documents folders via iCloud Drive); and when I see reviewers raving about all the Emoji possibilities, I want to tear my hair out.