I thought I'd start this thread in case anyone has some minor problems they'd like to share.
So far I've found a couple of problems in 8.1. The first showed up in Firefox, where I was getting fuzzy text once I scrolled down, and then back up the page. I didn't happen if I only had a partial screen in Firefox, and when the fuzzy text appeared, it would snap into focus if I clicked anything outside of Firefox. The solution was one setting in about:config in Firefox. Once I set gfx.content.azure.enabled to false, the problem vanished.
But this little problem never showed up in Windows 8 before I updated.
The second one for me was with my printer. It stopped working entirely. I had to delete it from the list of printers, then reboot and let the operating system find it again.
Anyone else with minor issues?