I still don't get the Windows 8 hate. Works beautifully on my Surface Pro 3. A few tweaks makes it great on my dual monitor desktop as well, even without touch screens.
As long as one can adapt to the full-screen start interface, that's about the only issue on desktop. Unless your searching for or going to select an app, you can accomplish most of your power-user tasks with a right-click on the Start button.
However, while I am mighty happy with Win 8.1 (8 was a little rocky, just due to lack of boot to desktop and I think shutdown was added to the Start right-click menu sometime later, either in 8.1 or in a patch).
It is super smooth, incredibly stable (Windows 7 was for me as well, but 8/8.1 is even faster!), and has a touch of new.
Windows 10 is where it all comes together and becomes freaking awesome. Windows 10 IS indeed what Windows 8 should have been, but they had to go down this route to figure that out. In 10, the start menu is back in proper fashion, albeit with a Windows 8 style and universal apps.
It'll have some initial bugs, but I'll be on Windows 10 from day one, almost assuredly. Having universal apps in a window is, alone, awesome. I like the mail client in a proper window, not full screen. And with free versions of Word in the "metro" style, also windowed instead of full-screen, are great. The free Word app, for instance, has quite a bit of capability compared to the full desktop app. It obviously lacks things, but for almost everything normal people do, it has what they need and then some. It's more fully featured than I expected, quite frankly.
There will be plenty of reasons for the desktop Office 2016 suite, but for a lot of users, they will be very satisfied with the free Office apps.