Oct. 26, 2012/ongoing: Windows 8 patches and firmware upgrades
There have been dozens of patches to Windows 8, Windows RT, the various Metro apps, and other Windows 8-affected products, including IE10. Windows RT firmware has been updated twice.
Windows 8 patches are documented with knowledge base articles, and security patches receive Microsoft numbers, as we're accustomed to. The problem is that there is very little documentation about what has been done to the other components. There's no change log for Metro apps -- even key apps. The RT firmware patches are basically undocumented, aside from very broad statements from Microsoft.
Have there been problems with Win8 automatic updates? Most certainly. Microsoft's documentation on the Servicing Stack Updates, KB 2771431, lists eight problems, all of which are apparently fixed by the latest Servicing Stack.