We've just received Assassin's Creed 2 and Settlers VII for review, and verified with Ubisoft that the DRM is the same as the boxed product. If you get disconnected while playing, you're booted out of the game. All your progress since the last checkpoint or savegame is lost, and your only options are to quit to Windows or wait until you're reconnected.

The game first starts the Ubisoft Game Launcher, which checks for updates. If you try to launch the game when you're not online, you hit an error message right away. So I tried a different test: start the game while online, play a little, then unplug my net cable. This is the same as what happens if your net connection drops momentarily, your router is rebooted, or the game loses its connection to Ubisoft's 'Master servers'. The game stopped, and I was dumped back to a menu screen - all my progress since it last autosaved was lost.