Not as bad as I expected. I loved XP, then finally bought Win7 since we were using it at work, and still are. I put up with the nagging for a while, but realised that eventually they would pull support from Win7 and if I didn't go with the upgrade, I would have to pay.
I never really bonded with Win7 like I did with XP, but there was less of a jump between XP and 7 than there was between Win 7 and 10. The Tablet aspects of the menu system, and the Apple-esque programs still trip me up.
The upgrade was easy, the easiest software install I have ever done. All installed programs were still there, still working.
Then it all went wrong when I tried to check an ancient Zip250 drive and the driver caused Win10 to go to an unrecoverable blue screen of death! I had to use another installation of Win7 on a separate drive to download a full install file of 10, which was free, and wipe my 128Gb SSD and start again. Interestingly, the SSD was almost full and I think that the upgrade to Win10 stored a huge amount of recovery data on my C Drive which was almost enough to make it unusable in the long term. I have read that Win10 has a reverse function to uninstall itself and that must mean it keeps all the earlier OS available. Fresh installation didn't do anything like that and there was plenty of space again.
Fresh install wasn't bad, but had a nightmare with some of the old software which required Java. The software needed a version of Java which was older than the oldest version that Win10 would run.
The Windows Picture and Fax viewer disappeared totally and was no longer available to preview photos, it was fine when I did the upgrade, but the fresh install hid it. I found a fix, but it involved a Registry Edit!
Overall I am happy enough using it. There are annoying aspects that result from the attempt to make one OS work for tablets and PCs, but most of the time I can work without noticing this. Nothing so annoying as I wish that I hadn't upgraded, but nothing so great that I would hate using Win 7.