I'm probably not the first one to run into this, but I thought I'd post a warning anyhow. Yesterday I was running 12.1 Beta 1 and did a "zypper update" on my laptop from the GNOME desktop. It managed to retrieve all the packages, but during the install, the wireless crashed, and then the X server crashed. There was no way to get back, and I ended up re-installing. So ... if you decide to update in place, do it on a wired connection from a console (init 3).