I am not starting an argumentative discussion here and this post is not about career development, but from the commercial point of view: If a company was using ASP.Net MVC as a main methodology to build their web sites and application. However, ASP.Net MVC takes more time to show a functional application than ASP.Net Web Forms, for example, building domain models would take some time which obviously can't be represented on a UI at that current stage.

My question is, if a client wants to see a functional demo application (just a proof of concept) so he knows that the company he is dealing with is professional and capable of doing that. Would it be better to do that demo in ASP.Net Web Forms only to show the client, and then work on the real application using ASP.Net MVC? If not, what are the (quick) alternatives?, I mean, if we tell the client to wait till we have a working demo (by ASP.Net MVC) we may lose the client and the whole project opportunity.