VBP compared with NANT
 

I need to find some advantages of Vis Build compared with NANT.
I need to make a presentation of our build process -for developers -and they use NANT on their boxes to build ,VisBuild is used only on production build box .
I am sure they will start asking why not to use free NANT instead of paid VisualBuild software .
I am very happy with Visual Build and the main difference I will write is VisBuild provides you an user interface for development -NANT does not do it -so it is much easier to develop the VBP projects and to follow a running build process.
But what about other differences?

As you noted, VBP provides a robust GUI front-end for easily designing, debugging, and maintaining builds, and VBP also provides many built-in actions for a variety of third party tools and common build activities, is regularly updated with additional features and enhancements (NAnt hasn't changed much in years), and purchases include (responsive) support, minor updates, and bug fixes. VBP is also very cost-effective, often paying for itself in time saved within a month or two.

Thanks for info!