IME, I prefer Windows 10 over any previous version. Yes, there’s a few changes they made that I don’t like, and there’s a few changes to the UI that took a bit of getting used to, but that’s just part of the game. The main thing I like about it is that it is noticeably faster than Windows 7. When I upgraded my previous system from Windows 7 to Windows 10, it booted in less than half the time, and after I fixed a couple minor driver issues, I even got significant frame rate improvements in games too. If it were just a balance of UI improvements I like vs ones I don’t, given some of the monitoring and patch changes, I’d probably have preferred 7, but the speed definitely makes up for it. But if you don’t notice or need the performance improvement, I can’t really blame someone too much for sticking on 7, other than that they missed the free upgrade that they’ll eventually have to pay for.
Other than that, I don’t think anyone would reasonably try to say it isn’t clearly superior to Windows 8 or Vista. I’d learned to tolerate Vista, since I had it at work for so long. And even though 8 was better than Vista, I hated it compared to 7.
As for XP, yes, it was really nice at it’s time, but Windows 7 (and Windows 10) are just strictly better. Everyone I know who’s said that (yeah, anecdotal, but I work in technology, so I have a lot of exposure) was pretty much someone who hated the idea of learning a new technology, even though I think the learning curve to Windows 7 or 10 is pretty minor. Every single time, even when it’s almost universally said to be better (like XP when it was new or 7 when it was), there’s always someone saying how much better the old one was. In a previous job, I’d started not too long after they’d finished migrating to XP, and I constantly heard people saying how much they prefered windows 2000 or NT. And the same goes for their server versions too, and those have pretty much always been the case where the newest is better than the last (though I do HATE the metro UI on 2012, the underlying OS features outweigh that).
I’m not one to say get on the bandwagon, but particularly when it comes to technology, if you’re clinging onto stuff from 5-10 years ago, especially against the general consensus of people who work with that stuff, you probably need to let go. And the older it is, generally the better your reason for clinging has to be. At this point, the only “good” reasons I can think of for XP is that some software someone needs isn’t compatible with newer OSs, though that’s generally more just admitting that they haven’t upgraded or looked for alternatives in the last decade. But hey, expecting a government employee to upgrade their system more than once every 20 years is sometimes asking a lot, apparently. And, yeah, that last one isn’t an exaggeration, they HAD to use XP because it was able to emulate 16-bit mode, because it had been THAT long since the code base had been touched, and their argument was that 15k lines is just TOO much to revisit (which it most certainly isn’t, that’s really not very big at all).