I've just quickly tried out gradle as a build system. I have three observations so far.

1) Netbeans have a pretty good integration

2) Repository configuration is in the build script. That is in my book a pretty big f*ckup, maven got rid of that with maven 2. I know I can write my own build script but a new build system where there is no convention for configuration of things that are specific to the build machine and not the source code... The irony of using Ivy and obscuring everything that is good with Ivy.

3) The run task... It is currently not possibly (said the forum 1 year ago and that's all I could find on this subject) to pass command line arguments to the application. You offer a "run" task but it is unusable.

If I have to write those things myself I might as well stick to bare Ant + Ivy.