[seabrookmx]

Not OP, but we built a product around it and though Camunda is reliable and fast enough for our use, the developer experience is pretty gross.

The BPMN gets saved out as an XML document, but the editor doesn't do a good job of making the format consistent. This makes changes to the BPMN basically impossible to code review without downloading the old and new copies and visually inspecting, which is a chore for large workflows. Especially when variable inputs and outputs require clicking into each node.

Small code snippets in either JS or a Java plugin (jar) can be embedded and used to massage variables and track state. These are also difficult to code review and test as you essentially need to write a harness that mimics Camunda to run them.

All of our new products are using simpler workflows via FaaS and queues (RabbitMQ). If we ever needed large workflows again I'd lean towards something like Airflow.