I have not seen ANY advantages in MVC over ASP.Net. 10 years ago Microsoft came up with UIP (User Interface Process) as the answer to MVC. It was a flop. We did a large project (4 developers, 2 designers, 1 tester) with UIP back then and it was a sheer nightmare.
Don't just jump in to bandwagon for the sake of Hype. All of the advantages listed above are already available in Asp.Net (With more great tweaks [ New features in Asp.Net 4 ] in Asp.Net 4).
If your development team or a single developer families with Asp.Net just stick to it and make beautiful products quickly to satisfy your clients (who pays for your work hours). MVC will eat up your valuable time and produce the same results as Asp.Net :-)