MVC vs ASP.NET

There are various positive points to Using MVC

1.  TDD support out of the box as most of the design is based on interfaces.

2.  SEO friendly URL by design (though now this is possible in ASP.NET 4 as well)
3.  No ViewState (this may seem a bit of moving backward to some), but overall a good design    decision.
4.  Clean View Markup (no additional HTML emitted)
5.  100% extensible.  You can add your own controller with IOC, switch view engines at will, control model binding at wish etc.
6.   Rich UI support (possible through client side JS libraries like jQuery UI and others).  Telerik has released some controls for MVC which includes Grid control as well (which are merely HTMLHelpers)
7.  Session, JS, Ajax works.  Validation is even more powerful with DataAnnotations and jquery.
8.  Is MVC faster?  Yes by default because of lack of viewstate and clean markup.  But performance is subject and MVC by design is more performant that traditional ASP.NET webforms (though webforms can be made as fast as required.
9.  Out of the box support for mitigating antiforgery attacks and XSS vulnerability (though asp.net does has this to some extent)
10.  Out of the box minimal IOC support.
11.  Full control over rendered HTML
12.  Pluggable architecture

***ASP.NET WebForms developers migrating to ASP.NET MVC initially feel a little uncomfortable because they are unable to find many key features that were available in WebForms approach. There are many questions comes to their minds like below:

1. Web is still stateless but where is the Viewstate?

2. Where is that Code behind file?
3. What is that Razor syntax? Why I need it?
4. Where to find Page_Load method? that is used to put code for almost every page.
4. What about Binding and Rich Server Controls? Where these controls gone?