I was a Maven hater and resisted it for a long time but over the years Maven has gotten much better, it's well supported in IDEs and as far as I can tell, Maven has replaced Ant as the de facto build system for Java projects. If you want new developers be able to easily build, debug and run your code via command or their favorite IDE then Maven is the way to go, and that's especially true for open source projects like Roller. That's why I spent a couple of weekends learning Maven and converting Roller's build process from Ant to Maven (ROL-1849). The process of conversion wasn't too difficult.
You can read more of Dave Johnson's entry, or you can watch this short video showing the ease with which you can now obtain and build Roller.