Similar to how it was with Vista. That was a pretty dire system overall when considered as the direct upgrade from Windows XP and many people had problems with it but not everyone did. Same thing with W8. I suspect that the same may be said of W10 in the future.
Personally, however, I'm happy to leave all my W7 boxen as they are. By 2020 all of them will have probably reached EOL and even if they haven't I'm more likely to drop Windows altogether by then as I do more on Linux than anything else, and the more that Microsoft attempts to bully their way into making me upgrade, the more likely I'll be to shift the remaining bits to Linux.
Are you Microsoft shills reading this?