Grouping ANT/Maven together because of XML is a very superficial association to make. ANT despite what it claims is essentially an inflexible programming language, which offers very few benefits over java (and many disadvantages), except that it is interpreted (not compiled), has a library of build tasks and can be stuck in the root of a project without looking like source code. XML is a big issue in ant because it is a very poor choice for writing a programming language.

Maven is a build framework, into which you make your program fit, by decomposing it into maven projects ... etc. etc. XML is a perfectly good choice for configuration here. The core problem with Maven is poor design. For one, it has tried to make things simpler than they are, and does not recognise that some programming projects are fundamentally not amenable to a module structure (i.e. what ebuild calls products). It also makes developing across the dependency boundary (i.e. your program + the library) very cumbersome indeed.