There's plenty out there about the lack of a start menu (which I, for one, used at length) and the inconsistent controls between the Metro and the desktop, so I don't need to get into it. (If you're not familiar with it here's a fairly clever and comprehensive animated review [https://www.youtube.com/watch?v=WTYet-qf1jo] of Win8.
But here's what you need to know:
TL/DR: Win8 restricts what you can run, what you can play and what you can do. Win8 tattles on you to Big Micro, and if MS doesn't approve, it can kill anything and everything on your system.
THE WALLED GARDEN
In order for anything to work as a Win8 application (meaning it accesses the Win8 features) developers have to run it through Microsoft's some are publicized [https://en.wikipedia.org/wiki/Windows_Store]). Many Most Almost all apps have to go through this certification process multiple times, costing a fee to Microsoft each time (another weight to sink tight-budgeted startups). Furthermore this process means you have another layer of censorship to blockade cool games from reaching its audience (that's you). (Incidentally, they used to not want anything unacceptable for teen consumption, but pressure forced them to change it. A number of major game devs are abandoning Win8 because of this new policy.)
This is a seriously bad thing.
THE SURVEILANCE CAMERAS
Does anyone remember when it came out that Origin was taking regular pictures of your directory and file trees and sending that back home? Is that still a part of the Origin ToS? Well, Windows likes doing that too. Any time you download something, Windows 8 knows, and sends that info back to HQ. Smile, you're on Microsoft Camera! Furthermore, lets say that you have a keen app, but Microsoft decides for whatever reason they don't want you to have it (and considering their Xbox policy, they decide often). Bam! It's gone. And if it fucks up your system or your very important data, well Microsoft's ToS says you're screwed.
This is a seriously bad thing.
THE RUSTED GATES
There's that part where Microsoft was supposed to update security protocols so that only Big Micro could create a proper signature once a program was thoroughly tested for malware. Well, they didn't. Some suggest that it's because the US government found a backdoor (Remember Stuxnet? Remember Flame? Remember Stars?) and wants to retain it. Still, they didn't upgrade the protocols and have left you and your computer open to the NSA and whoever else has cracked the old Windows signing protocol.
This is a seriously bad thing.
These and many more fun interesting facts can be discovered here [https://www.fsf.org/blogs/community/friends-dont-let-friends-use-windows-8].
You are seriously better off downgrading to Windows 7 than staying on Windows 8. And what frightens me is the lack of mainstream publicity that any of this has gotten.
And the interface just sucks.
238U