Ask HN: What BPM solution do you use?

I've used Oracle BPM in large enterprise projects, it is a good product, although one has to pay a fortune to license it. For smaller projects I am looking for alternatives, and currently evaluating Camunda. It is open source, lightweight, but it is not clear how to work with business data. One has to create own UI forms, as the existing feature is far away from being suitable. What other alternative exist that you can recommend?