Main advantages of ASP.net MVC.

• Separation of concerns (SoC) • From a technical standpoint, the organization of code within MVC is very clean, organized and granular, making it easier (hopefully) for a web application to scale in terms of functionality. Promotes great design from a development standpoint.
• Easier integration with client side tools (rich user interface tools) • More than ever, web applications are increasingly becoming as rich as the applications you see on your desktops. With MVC, it gives you the ability to integrate with such toolkits (such as jQuery) with greater ease and more seamless than in Web Forms.
• Search Engine Optimization (SEO) Friendly / Stateless • URL's are more friendly to search engines (i.e. mywebapplication.com/users/ 1 - retrieve user with an ID of 1 vs mywebapplication/users/getuser.aspx (id passed in session)). Similarly, since MVC is stateless, this removes the headache of users who spawn multiple web browsers from the same window (session collisions). Along those same lines, MVC adheres to the stateless web protocol rather than 'battling' against it.
• Works well with developers who need high degree of control • ASP.NET web forms automatically generates much of the raw HTML you see when an page is rendered. This can cause headaches for developers. With MVC, you have complete control over what is rendered and there are no surprises. Even more important, is that the HTML forms typically are much smaller than the Web forms which can equate to a performance boost - something to seriously consider.
• Test Driven Development (TDD) • With MVC, you can more easily create tests for the web side of things. An additional layer of testing will provide yet another layer of defense against unexpected behavior.