As far as I can tell, 10 has no killer feature, but has incremental improvements in a few areas that will be more relevant to some than others. It has better built-in support for modern hardware: common examples are USB3, NVMe, high-dpi monitors and touchscreens. It has some improvements under the hood in terms of security. It has DirectX 12 for gamers.
Well, I happen to like Hyper-V in the box, it tends to work better than VirtualBox or VMWare for that matter (at least in my experience)... Windows 8 pro comes with it too, but Win10's UX is finally there, where I hated windows 8's and would always revert to Classic Shell.
I also disabled Cortana and most of the search features beyond basic indexing and likewise don't use sync... I don't like the occasional Edge browser ad above my Chrome icon in the taskbar though. I'd still rather W10 than Linux... I use Ubuntu on my HTPC, and really like Unity, but it's just not quite as good, and there's the pretty regular quirk after updates run that I spend hours hunting down a solution for a few times a year. I also happen to mostly like my macbook, but there's not a viable solution to replace my main desktop.
I don't want to customize everything, I want nice defaults, where advanced features are tucked away... I also don't want to spend another 2 hours a few times a year fixing whatever problem the latest round of updates have caused. much more rare in windows in my own experience, I know two people who have had bad aftermath from updates, but one turned out to be bad ram that caused the issue.
All the same, I would much rather have macOS with a start/taskbar a little closer to windows... the instance previews are nice, and it's a bit easier to work across multiple monitors... Most of my time is spent in VS Code and a couple browsers, so as long as I have bash (comes with git in windows), I'm pretty much good in any OS...
