This a great framework, i've been using it for over a year now. It's been iteratively released (to public) 10 times, which is a new way for MS to develop, and they have really listened to the feedback from its users.
Visual Studio + asp.net mvc is a highly efficient dev. enviroment.
I agree. It's great because it's essentially Rails ported over to .NET. That's not a backhanded compliment. I think it was the right thing to do. I know there are a bunch of Rails skeptics out there, but as far as development practices go, they made solid decisions at every step. Coming from conventional ASP.NET over to ASP.NET MVC should be a breath of fresh air. No more having to program on a platform that tried (and IMHO failed) at making web development be more desktop-development-like.
I've already decided against doing ASP.NET development on my own projects, but if I were forced to use ASP.NET, I wouldn't think twice about choosing the MVC version over the conventional one. I had already begun introducing the Castle frameworks (inspired by Rails) into ASP.NET projects well before ASP.NET MVC was even announced, so I can't help but praise MS here.
Visual Studio + asp.net mvc is a highly efficient dev. enviroment.