I manage several WP-powered sites. I just upgraded all of them from 3.3 to 3.3.1 and watched how the automatic update process broke the front-end (preventing it from loading at all) in many of them; I couldn't get those sites to work even deactivating all plugins and switching to Twenty Eleven theme. I restored a backup, performed a manual update, and everything worked like a charm.
It didn't happen in all of my sites, some of them applied the automatic update just as expected.
I didn't have yet the time to track this down, so I don't know if it's a WP bug, a plugin-related issue or what. But still wanted to share it with you guys, in case someone else is having similar problems, so we can collectively work it out.