I'm primarily a Windows user (but I run Linux on some of my devices as well). I'm also tend to be quite particular about my UIs getting things right. Saying all that, I've felt next to zero impact in moving from Windows 7 to Windows 8.1. Windows 8.1 feels a bit snappier. Some options have been moved around a bit. That's about it.
I just don't understand all the polemicising. Especially with statements like: "The specifics of what's wrong in Windows 8 don't really matter". They matter to me, because after reading all these articles about how terrible Windows 8 is, I still can't figure out what those specifics are! I would love to be enlightened about what I've been missing (or how I've been using Windows 8 wrong).