Windows 8.1 is far, far better than Windows 10.
You can de-stupidize Windows 8.1. I'm a purist when it comes to UIs (Windows 2k is my reference for a nearly perfect UI), and even I liked Win 8.1 with Classic Shell (Classic style cascading start menu), Old New Explorer to ditch the ribbon, 7+ Taskbar Tweaker, lots of registry edits, app eradication via install_wim_tweak, and a custom theme (Classic in appearance, but uses WDM). Classic Shell has an option to block the Charms, and I used Metro Killer to make sure it never darkened my doorstep.
Once you scrape off that tablet crap Microsoft tried to tack on, it's quite solid. It sounds like a lot of work to get to a usable UI, and it is kind of stupid to have to fight MS so much to be able to be a happy user of their own product, but I had used almost all these things in Windows 7 anyway, even though 7's out of the box interface is far, far better than anything that came after it. If I was going to use all these tweaks anyway, why not use them on 8.1 and get three more years of support? (It turns out I didn't need them, as the migration to Linux that I started in 2015 is already done more than a year before 7 goes out of extended support, but I didn't know that would be the case at the time.)
Win 8.1 doesn't come with huge, time-consuming, buggy updates twice a year, and the updates that do come are fully controllable and don't cause the kind of issues the 10 updates pretty much always do. It shuts down when I want it to shut down and it can be left idle forever, and it still won't start installing updates. It doesn't try to serve MS or monetize me. It never uninstalls the programs I want installed or installs programs I do not want installed. It never removes my drivers and replaces them with whatever ones it thinks are better. It never changes my settings back to those that serve Microsoft... not to mention that it doesn't have 100 settings you have to change to get it to (partly) stop serving Microsoft. The telemetry MS backported to 7 and 8.1 is easily removed, since it was just kind of tacked on, not baked in as it is in Windows 10.
The loss of control over my own computer is the worst thing about 10, the real deal-breaker, so there's just no way that Windows 8.1 could be worse than that. I don't consider the 10 interface to really be any better than 8.1... they both boot to the desktop, not the start screen (option added in 8.1). One has a full-screen start menu with ridiculous tiles, the other has a partial-screen start menu with ridiculous tiles. Neither of them are any good, but I don't particularly see any big advantage in the Win 10 one. Win 8.1 and 10 both use the hated ribbon in File explorer, and they both have a ridiculous Settings app... though in 8.1, you can get by without Settings. There are only a few things moved to Settings in 8.1 (like Bluetooth stuff), but I have always found alternative ways of doing things. Not so in 10, where MS is gradually phasing out the good and desktop-appropriate Control Panel in favor of the bad and desktop-inappropriate Settings.
Windows 8.1, suitably modified, is the answer for people who can't migrate to Linux at this time but who want to keep getting updates for Windows beyond the drop-dead date for 7.