Visual C++ Compiler November 2013 CTP: Error 0x80070666

The Nov '13 CTP is a compiler upgrade that adds a ton of C++11 features that should've already been there. Keeping with the spirit of your typical Windows package installer, you might get this cryptic error:

Error 0x80070666: Cannot install a product when a newer version is installed.

...when you've obviously not installed this. It's caused by the installer detecting visual studio redistributables as newer versions of itself. Removing all newer-than-nov2013 redistributables fixes the issue. Good job Microsoft!