At camptocamp we use Gradle for all of our Java projects now. It slims down
the project build configuration by about 1/2 or so and some of the hacks
required by maven unnecessary.
Migration from Maven to Gradle will likely be some work since Gradle cannot
call Maven plugins so Ant replacements will have to be used for those cases.
Although I don't know how much plugin hackery we have in our build system.
As for maven 3, It does boast some improvements, especially around speed
but it was mostly a re-write of the internals so it won't clean up our build
system but a speed up would be nice.