I've been waiting for someone else to go first. Glad to hear you had a relatively painless experience with the upgrade. Guess I should give it a go soon. Most of the reviews I've read say that this is one of the better Windows to come along. Gaming wise, I've only read about marginal improvements in performance over Win 8.1, but Direct X 12 has a ton of potential. Good article here:
I have a Lenovo thinkpad tablet that I upgraded from 7 to 8 to 8.1 to 10. W10 is ok and least in its' "stock" form shares some backward usability with 7. While still retaining the tile from 8, you can use a modified taskbar similar to 7. Not quite the same as the standard shell/task menu but it's much more usable. Think that the Classic Shell utility is a better fit for most typical users but if you don't really have to have it, the standard OEM shell works ok.
I've used LoL and Pillars of Eternity on it which both were installed on the 8.1 OS so that stuff made it across ok through the upgrade. Standard utilities like CCleaner, AV, Malwarebytes work fine as well. Openoffice is ok too on it. No real problems other than having to find some Lenovo specific drivers for weird firmware and 8/8.1 versions of those seem to have worked ok.
It had a major update a couple of days ago and made it through fine; just make sure your disk is clean (chkdsk /R) , there's enough free space, the existing OS is patched up and cleaned up (no unusual Event errors).
PS : probably should check 1st for latest drivers too, I had to do that after getting through the install anyways for specialized things.