Ant is the first Java build too that I used. I am currently using Maven as my primary build tool, but sometimes I found that it is very troublesome to use. The dependency management concept is good but the way Maven behaved sometimes is not up to my expectations or requirements.
Next come Ivy. Apache Ivy is now a Ant subproject. Ivy is a dependency manager and using it together with Ant I found that they are extremely flexible and easy to use. You can find a interesting comparison between Maven and Ivy here. In short, Maven is a software project management and comprehension tool, whereas Ivy is only a dependency management tool, highly integrated with Ant, the popular build management tool. So maybe a more interesting comparison would compare Ant+Ivy vs Maven.
I am trying to use Ant + Ivy in my new project. In future I will tell you more about it versus Maven.