Let's have a look at the upgrade:
Choose "Upgrade this Configuration Manager site" to start installation
A new feature in SP1 is that more Server languages are available now
During Prerequisite check a new warning message is shown on collections
And finally after a "few" minutes waiting the installation is done! :)
Very nice to have a lab environment with ConfigMgr 2012 SP1 now!!
Just start to download the bits and experience the new features and functionality yourself. More on the new stuff can be found HERE. Hope you like it as much as I do! More to come about SP1 later.