I didn't really see the problem with Win 8.1 - it seemed to work fine and I'm not very techy. Nevertheless, I've upgraded two computers to Win 10 and they seems to work well too. I had a problem with the task bar on my ultrabook the other night - but, in the end, that turned out to be ludicrously easy to fix and left me feeling like a bit of a dork. The only real problem that I've encountered, so far, has been with getting my ultrabook to speak to my digital projector (it worked with Win 8.1). I'm sure that there's a work-round for that too but I'm giving a talk next week so will take my ancient, extremely heavy, steam-driven (Win Vista) Toshiba lap-top because I know that that works!