I have a friend who makes his living supporting IT for small businesses. All his customers were running Win 7. Some of them wanted to upgrade to Win 10 but my friend advised against it.
One business owner insisted and over the weekend she went to her business and upgraded all their PCs to Win 10.
She called my friend for help on Monday morning. It took him the better part of two weeks to restore everything. It cost the businesswoman a pretty penny.
I feel sorry for anyone in IT that has to put up with Win 10.
I work for the Navy. NMCI upgraded to 10. One fourth of the computers in my code CRASHED during the upgrade. I was lucky.
But for some reason, EVERY DAY at 1300 my computer slows down to tortoise speed for about half an hour.