I installed windows 8 on my computer when it was new. While the timing wasn't that great (it was a couple weeks until 8.1, and that really wasn't a small update or service pack), in the end it wasn't worth it. Yes, it booted a couple of seconds faster. But with a modern PC you'll need a chronometer to tell the difference. And the interface...you know that "you can turn it off" isn't really an argument in its favor, right? With some tweaking, I managed to make it behave pretty much as much as I had used to on my old PC (which I still have).
...and then windows 8.1 came along and every setting got fucked up. Why is it that linux distros like ubuntu and mint install so smoothly that you can pretty much upgrade the entire operating system with a couple clicks as if it was a browser update (with about the same chances of programs no longer working as firefox add-ins...or even a LOWER chance), and that microsoft seems to think we want to format our entire SSD-drive if we want to UPGRADE FROM 8.0 TO 8.1???
Admitted: it wasn't a legal windows 8 installation, but I honestly think that wasn't the culprit.
To a degree, I respect MS that they overhauled their interface. With tablets, smartphones and a new console on the way, it's certainly a good idea if they all have a similar way of navigating.
Unfortunately, that navigating is just bollocks on a non-touchpad interface. I mean...you know how installed programs often have these extra icons in the start menu (like "game", "game safe mode", "readme", "uninstall"...and so on)? I really thought that metro interface just showcased the main program and had the others hidden somewhere (like on a right-click or something). It isn't. It's just not there. It just isn't. Not even in the non-metro interface. I can only hope that they added it back in 8.1, but I couldn't be bothered to install that correctly. For all 8 was doing, it seemed like it was slowly getting in the direction of 7. And that's the point: 7 already exists, is stable and is easy to use. Aside from the boot time, it's pretty much exactly the same performance wise and all the extra's are things I don't care about (honestly...is anyone really using the windows shop over already existing programs or freeware?).
All in all, I can't think of anyone updating to windows 8 aside from "because I want to upgrade". That same irrational behavior that makes people want to update their consoles to the latest firmwares despite it only blocking potential piracy exploits. I've learned the stupidity of that sort of thinking when installing windows millennium, and I've given windows 8 a fair chance to convince. It failed.