Umbraco 6 brings new lots of improvements for developers, new datalayer, new API’s and complete support for Asp.net MVC 4. This means developers will have greater control, simpler code and higher productivity when developing with Umbraco.
As the umbraco blog says, in Umbraco 6 we have:
MVC support,
Native Razor support
Strongly typed views
Building custom controllers
Whole new shiny...