* Free OS updates.
* Better touchpad support throughout the entire OS.
* Vastly superior HiDPI support (especially if you're using a multi-screen, multi-DPI setup). I cannot stress how poorly Windows 10 performs in this regard. This has been a solved problem on the Mac for years.
* Better colour management through the whole UI stack.
* Better tablet support (OSX has had integrated support for tablet events since 10.4, on the Windows side there were still apps that broke when the Surface 3 launched almost a decade later due to using a third-party API for tablet events that needed custom drivers)
* Core Audio. OS X has had the same set of audio APIs since 10.3, and they've been well regarded for years and years. It wasn't until Windows 10 that you could argue Microsoft had finally caught up, and there's still people with ASIO driver compatibility issues. That's literally 12 years it took for Microsoft to catch up.
* OS X had scrolling of inactive windows for over a decade before Windows caught up. I actually think it's something that was there in 10.0 but I only started using Macs at 10.3 so I can't be sure.
* Spotlight. Spotlight is almost the perfect analogy of the difference between OS X and Windows, and I'm just going to look at one tiny feature of it. If you want to do some math on Windows at a single keypress, you need to turn on Cortana which only became availble in Windows 10. Cortana isn't even available in every country. Meanwhile OSX has had that built into Spotlight since 10.4 and it works on every Mac ever shipped since then, no matter what country you're in.
* File tagging. OSX has had this for over a decade, and you still can't do it in Windows.
* An integrated C/C++ runtime library, like every other Unix ever. It wasn't until Windows 10 that you could ship C/C++ code without worrying about whether your end user had the right msvcr/msvcp DLL installed on their machine.
I'll stop here, because there's so many things that OSX has had for a decade or more that Windows still hasn't caught up with that I wouldn't be surprised if Windows doesn't catch up after another decade.