Windows 7 works fine and fits my needs, Windows 10 does not. Why switch? So far, the only reason Microsoft has proffered for me to switch is that it makes life easier for Microsoft. Sorry, but there has to be a better reason than that.
Better CMD, better snipping tool, cortana can be usefull sometimes, autocorrect on start (type nopepad and enter), multiple desktop. That on top of the few things that Windows 8 did right. Too little, but why not?
Every program is a part of some other program, and rarely fits.