One for you all to be aware of with regards to SCCM on Server 2012 with WSUS....

Just rebuilt SCCM 2012 onto Windows Server 2012 and had some trouble getting WSUS to Sync.
It was failing to find a valid Sync Source even though it could see my WSUS server.

After a bit of googling I found what appears to be a bug with the Registry value for one of the WSUS service (WSUSService) for Windows Server 2012:

It has a space in the pathname, but isn't surrounded by Quotes, so the service fails to start.

The mystery of the WSUS Service not starting in Windows Server 2012 | Enduria - by Guido van Brakel

Once the Quotes are added, the WSUSService service starts and SCCM can then sync with WSUS.