Maven also suffers from XML hell, but at least it has dependency management.
I've used gradle extensively and it is quite difficult to figure out what is going on. Using a debugger would be nice, but it simply doesn't work. Gradle is terribly slow on a big project, the update checks are the main culprit. They should be done automatically in the background to alleviate this pain.
Since gradle is compiled rather than interpreted, calling code in the project being built is difficult and convoluted. For example, if I want to call a DBUtil.cleanDB() method in my java code I can't reference DBUtil in my gradle script as it hasn't been built yet and the Gradle script won't compile. If gradle was interpreted this problem wouldn't exist....
I find the DSL unintuitive and the inability to specify the order of tasks execution is always a sore point.
On the positive, at least it's a language, not XML. I have never understood the java world's obsession with XML and forcing it in directions never intended. This XML obsession has led to java being a major laggard in automation tech. Java devs do many things manually that a Ruby/Python dev would be horrified at....