VBP compared with NANT

[teognost]

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?