Nothing really important here just a story about things that do and don't work. I have a Dell XPS 8100 (ex Win 7) upgraded to Win 10 and a new Dell XPS 8700 with Win 10 installed.

Problem with the XPS 8700...oops your Dell 1320c Color Laser printer doesn't have a Win 10 driver so it won't work. Interesting, it works fine on the XPS 8100 upgraded to Win 10. So an upgrade didn't replace the driver and the old driver won't install correctly on the XPS 8700. Work-around - the wife's Win 7 upgraded from XP will act as a print "server" so score one for an upgrade.

Problem with the XPS 8100 upgrade is some strange Intel disk related software was taking 23% of the CPU power for hours and hours. After a few experiments it turned out to be okay to uninstall the Intel stuff and the original Win 7 drivers made the system happy. The same Intel stuff is in the XPS 8700 but it is not taking any noticeable CPU power so it is happy. Score one for the new Win 10 computer.