ArsTechnica has an excellent review of Windows 8. Anyone who is thinking of updating, should read this review, as it sounds like a weird mishmash of a touch interface and the old desktop that is not entirely successful on either.
I tried out the first developers preview and wasn’t a huge fan of the Metro interface, but at least it still had a start menu, the lack of start menu just seems odd, especially for desktop users.
There is also a seperate article on doing an upgrade install to Windows 8 from Windows 7. This is interesting as it is cheaper to do a download install than to get the DVD to install (at least it is still an option unlike for Mac).