http://blogs.msdn.com/b/diego/archive/2009/09/08/to-pi-or-not-to-pi-with-ef4-that-is.aspxA customer recently asked if there is still any advantage in using the entities that Entity Framework 4 generates by default instead of POCO classes. Another way to look at this is: why are non-POCO classes that inherit from System.Data.Objects.DataClassesen-USTelligent Evolution Platform Developer Build (Build: 5.6.50428.7875)