I once did an Ant to Maven conversion job on around 10 mature projects I didn't code. So that a large enterprise can move over to Maven and reap the productivity benefits.

Various Maven modules were restricted, including Antrun. Because the projects are old and tied to their directory structure of resources, it was more practical to script in Maven rather than follow conventions. Scripting in Maven was quite... challenging.

In this case, the problems arising from Maven also stems from the organization's context.