Ivy seems to be trying to resurrect Ant, when it should stay dead in my opinion (unless you are a lone developer on the simplest project). Maven is a more proper build tool with some workflow functionality that falls short outside of a small team of developers with no audit or control requirements. Both are vying for prominence as the open source build tool, yet trying to settle into compatible niches like two brothers hopeful for the throne.

Here is what Ivy says about Maven: http://ant.apache.org/ivy/m2comparison.html

And here is Maven’s side of the story: http://docs.codehaus.org/display/MAVEN/Feature+Comparisons