Microsoft has released SQL Server 2012 Service Pack 1 Cumulative Update 7, which is Build 11.0.3393.0. This CU has 47 fixes in the public hotfix list, a number of which seem to be quite significant for performance and stability.
Here are fourteen database engine-related fixes that are in SQL Server 2012 SP1 CU7:
This cumulative update is only for SQL Server 2012 Service Pack 1 (so you must be on Build 11.0.3000 or higher). If you are running SQL Server 2012, I really think you should be on the Service Pack 1 branch by now (or at least be planning to get there soon).