Look! Something new from a big company
Let me instantly hate on it without even trying it out
<---win10 user, I'm still alive and everything on my computer is working just as before. Nobody jumped out of my screen to put a chip in my head either.
Way to miss the point. If it works, great. Sometimes it doesn't.
Let's talk about facts, eh?
As someone who often upgrades to the latest and greatest for testing purposes, has upgraded machines for the company I have worked for, and has upgraded (or attempted to) several machines of my own and about 10 machines for friends and family, I have a pretty good idea about success rates.
The success rate stands at 100% for my company - but these were all newish (<2 years) high-end desktops. No tweaks required.
Of the external desktops I have worked on it stands at 100%, but only if you discount the 30% that I had to do stuff to get either obsolete video cards (e.g. Geforce 7600 ~10 years old) or wireless dongles that
aren't very old to run properly. (often by just forcing the install of Win 8 drivers). A lot of the people I have done this for wouldn't have been capable of doing it themselves, and they would have been stuck with a shonky system (until I reinstalled the original Windows, of course).
Of the external laptops, my success rate stands at 60%. Of that 60%, there were several issues with touchpad drivers, but this was often fixed by rolling back to an older driver, and doing some reg massage to ensure the updated one didn't reinstall (in many cases this seems to be fixed now). A couple had issues with wireless, where they wouldn't connect until after a reboot. This was eventually fixed by changing some device settings that never had to be touched before.
So that leaves a 40% mix of laptops, none especially old (in fact the oldest one, 8 years old, only had touchpad and wireless problems I could deal with), that either failed to boot, or booted into something useless, or did either of those a couple of months down the track after a major update.
In a couple of cases this appeared to be Windows 10 doing something to the UEFI partition. (These were Toshibas that have an especially crappy UEFI setup, so probably that's Toshiba's fault). Welcome to an unusable system - a blinking white cursor.This is shit that is not recoverable from, other than reapplying the image that you (hopefully) made before trying the upgrade.
The others - not sure. Drivers or something bad enough to make the machine unbootable.
A couple borked during install, but managed to automatically roll back. (Unfortunately they have "accidentally" been upgrade-attempted a couple of times - this can be annoying)
Apologies for the wall of text.
TLDR version: sometimes there are good reasons why you don't want to upgrade, leaving aside the fact that you might like what you're currently using.