What do you like best?
Unlike similar build tools in JVM ecosystem, Gradle does use XML but rather a flexible DSL based on the Groovy programming language. This leads to a short and clean build configuration files. In addition, Gradle is the de facto build tool for Android which means it has a wide adoption. Also, Gradle DSL is designed to solve divers problems that face developers as part of the software life cycle like: compilation, testing, static analysis, packaging and deployment. Thus, it integrates easily with continuous delivery workflows.
Furthermore, Gradle support a parallel execution mode which may speed up it's tasks.
What do you dislike?
Gradle learning curve is more demanding than other build tools, and there it needs some special preparation to start using it. For most Java projects, Maven works just fine so some people will not bother switching to another build tool with a completely different approach. Gradle is flexible, it allows to script anything but this means for large teams it will be harder to maintain a standard workflow (test, build, delivery).
Recommendations to others considering the product
If you're building Android applications, Gradle is a must to have as it is the defacto build system.
What business problems are you solving with the product? What benefits have you realized?
I was first introduced to Gradle, few years ago, as part of the Android software development when Gradle become the officially supported build system. Before Grandle, building Android applications was painful as it was mostly manual or the through the IDE. Though there was a maven plugin but was a community project and not a long term supported. After Grandle become the build system for Android the gain in productivity was huge, testing and packaging applications become a very easy task.