One of the features provided by RIA services is that your server-side model objects get automatically proxied in your Silverlight front end and are automatically serialized back to the server for operations such as saving to the database.
This seems to be a very similar goal to what "Self Tracking Entities" are providing, which is a technology developed by the ADO.NET Services team.
http://blogs.msdn.com/b/adonet/archive/2010/05/14/self-tracking-entities-in-silverlight.aspx
Are these two technologies solving the same problem? Or are they solving subtly different problems? Is one "better" than the other in certain scenarios? What are the pros and cons of each?