I am evaluating BPM offerings to be used within our application. I wanted to find out
the good thing about jBPM5 is that is completely integrated with Drools and Drools fusion, allowing you to model and execute complex business scenarios. At least in my experience once you get the process engine the next step is to integrate it with a Rule Engine and probably with complex event processing features. jBPM provides all of this out of the box and the good thing is that you don't need to learn different APIs to use all the features.
You also need to evaluate the tooling that in jBPM5 supports the complete lifecycle providing you tools for authoring your processes and rules and a repository to manage and store your processes.
Another good thing is the jBPM5 community, there are a lot of people adopting the project and a book will go out before the end of the year.
Hope it helps Cheers