Service Pack 1 has been out there for a while with a lot of great new features! There are some things to think about when upgrading and existing Configuration Manager 2012 environment.I have tried to collect useful information here to make it easier for you to upgrade to Service Pack 1.
1. Read the “Planning to Upgrade System Center 2012 Configuration Manager” on Technet
2. Download the hotfix for SP1 which solves an issue deploying the Configuration Manager 2012 SP1 which you will need, the ConfigMgr client installation logs
“Couldn’t verify ‘C:\WINDOWS\ccmsetup\MicrosoftPolicyPlatformSetup.msi’ authenticode signature. Return code 0x800b0101” in the ccmsetup.log file. http://support.microsoft.com/kb/2801987
UPDATE 26/1 2013
If you download the SP1 media after the 25/1 then you don’t have to download and use the update above.
3. This article describes the upgrade process http://support.microsoft.com/kb/2801416
4. There is a great list at myITForum with knwon issues as well, which is updated with new information all the time “System Center 2012 SP1 Woes, Gotchas, and Workarounds” I recommend reading this list before upgrading!