My Dell all-in-one has Win 8.1 on it, and even after having it for almost 6 months, I still hate it ! For months, I was afraid to open my pictures file; because it just "took over" and I could NOT find the X to get back out of it. I (by accident) discovered that it hides at the top of the screen, but if you get the mouse up in that top right corner, then the little rascal appears and you can shut the program down. Up until that amazing discovery; I just shut the whole pesky computer off and restarted it when i got something open that i couldn't close again.
Some things I can X out of and sometimes, you have to do a up-down swipe, or again a sideways swipe. Most of the time I use the regular normal-looking desktop screen, and that is much easier to deal with.
I stay completely out of the computer room unless it is something that can not possibly be done with my iPad, and only then do I force myself to use that Dell. I have no idea if Win 10 will be an improvemant or not; but like Josiah said, it will probably involve another learning curve. I don't think they make these things for Senior Citizens !