For troubleshooting help, see
Load Data into MDS More Easily
Loading data into MDS has become easier. You can now load all members and attribute values for an entity at one time. Previously you had to load members and attributes in separate batches.
Redesigned and Higher-Performance Web User Interface
The Explorer and Integration Management functional areas of the Master Data Manager web application have been updated with a new SilverLight® look and feel. You can now add and delete members more quickly, as well as move members in a hierarchy more
Installation is Part of SQL Server
You can now install Master Data Services while you’re installing SQL Server instead of using a separate installer, as was required in the previous release. You can install Master Data Services by using the SQL Server Installation Wizard or a command prompt.
Review the full set of SQL Server 2012 RC0 release notes.
In the release notes, there is a list of APIs that are not intended to be used directly from your code. For a list of these APIs, see MDS
Internal APIs (XPS document).