OSX, as sibling pointed out, but let me be much more specific:
- iMessage
- excellent integration between Contacts, Maps, iMessage, Mail, and Spotlight
- Mail.app, the best desktop mail client (IMO)
- Siri > Cortana > Whatever tarball you are expected to run autoconf inside of to get your linux box to act like a mac from the 90s
- excellent HiDPI support (neither Windows nor Linux have figured this out yet)
- plug and play external display support
- configuration-free lid switch sanity
- configuration-free trackpad sanity
- Lack of vendor adware (Windows obvs, did Ubuntu ever remove those Amazon search things?)
- painless FDE (extremely important)
- good fonts
- iOS development possible
- the most common modifier key is where my thumb can reach it and is not overloaded with the unix modifier key (is ctrl-c copy or SIGINT?)
- copy and paste work between apps using consistent keystrokes (windows figured this one out, linux not so much)
- less malware than windows
- an order of magnitude better a11y than anyone else in the history of OSes (it’s literally not even a race anymore, Apple is so far ahead here)
Finally, in not-OSX:
- build quality, even with keyboard and thermal issues, is still simply a head and shoulders higher than everyone else
The only people who could reasonably challenge Apple’s level of fit and finish from an OS perspective are Google, which is why I carry an rMBP and the 16gb Pixelbook. ChromeOS these days is a fucking marvel, up there on quality par with google search before answer cards, google assistant, and google maps. It’s a major achievement and is the first actually workable/usable Linux desktop.