Do we need another build tool? Make is never ideal. Ant is interesting, especially because it is part of the Apache Jarkata project. Two interesting points from the Ant project --

The Ant 2 effort -- Read the collected user requirement documentation -- Simplicity and Understandabiilty are the two main goals of Ant 1 and 2 (Extensibiity is the third).
From the Ant in Anger tutorial paper -- Limitation of Ant: It is not meant to be a nice language for humans : XML isn't a nice representation of information for humans.
While we cannot escape the use of XML as a definition file format for most software tools now, don't forget that it is used more for the fact that there are tools (parsers etc) that make processing XML easy. It is not easy on the people creating or reading them.