BuildR and Gradle are tools for multi-module builds where the build files are defined using a real language and task based (Ruby for BuildR, Groovy for Gradle). The benefits of a real language is that it is easy to create utility methods, control structures etc. Being task based (where 'task' is not the same as in ant, but rather as a Make target) means fine grained dependencies and lifecycle through invocation of dependencies.

In this writeup, I try to compare the tools, to help people choose the one they want.