http://www.useit.com/alertbox/windows-8.html
Devastating verdict.
I especially recommend the links to materials he gives in the last paragraph and at the end. There is plenty of information (hundreds of pages) on details and principles of handling design that I usually summarize under the simple term "ergonomy".
And ergonomy seems to be something that Windows 8 has no clue about.
In case you never heared of Jakob Nielsen, he is no unknown:
http://www.useit.com/jakob/