I hated Maven until I tried the alternatives.
Gradle's purpose is to muscle in on the consulting / conference market for Ant, just as Grails's purpose as wrapper around Spring and Hibernate was initially to muscle in on their consulting businesses. Now they've hooked in enough users, their bait and switch business strategy is now to screw them for as much money as they can.
So if you use Gradle now, you'll pay the cost later on after Gradleware is sold to some GE or VMWare or EDS or Oracle.
Advocating Maven over Gradle is just a joke. I routinely do things in Gradle scripts that would require writing an whole new plugin to do in Maven.
Also the plugin ecosystem is not as wide as Gradle and SBT lacks a daemon, which makes builds 3X/4X faster in Gradle.
For Java builds (especially multi-modules builds) I still prefer Gradle.
Please, explain incomprehensible (or show an example)
To be fair, I'm doing things that are actually bad and wrong. (At which point ant-contrib is your last friend.) Ant does its actual job - makefiles for Java - pretty well once you know it. It's fine, y'know, probably pretty much complete.
To my eyes, the build scripts are pretty clear. I like the way the scripts are nicely organized using 'apply'. Maybe the only script that may look complex to someone starting with gradle is 'convention.gradle', but again, nothing impossibly hard to grasp for a developer.
I am not able to maintain these build scripts. This is the problem with DSLs in general. Maven isn't great, but its strength is standardization. I can look at any Maven pom and know what it does and make changes to it.