One thing that I'll add that I don't see anyone else noting is that the update fails during the download at 11% - all the time, for me.
I'm trying to install it on a system that has a fresh install of Windows 7 Home Premium 64bit. No other software has been installed at this point. Right now I'm doing an in place upgrade to see if that helps, otherwise, I'm stuck trying some of the things that people have suggested earlier on in this thread.