Bonita soft and JBPM are two workflows engines. There're a lot of differences between the two engines althought both trying to solve the same kind of problems. I suggest go to google for any kind of comparaison, but basically jbpm is an engine, and bonita is an engine with UI layer ( I think that might be the main difference what you might be interested ).
The first question you should consider is if you have workflow problem or document management problem. You have 1 workflow and a lot of documents, then might be you have DMS problem. You have 20 workflows and a lot of documents, then might be you have workflow problem. You can work with OpenKM embeded workflow engine or you can connect OpenKM with thirdparty applications like bonita. In a huge workflow scenario my suggestion should be choose the workflow engine what fits better your needs and then connect openkm with webservices API ( here openkm acts as an slave ).
The first question you should consider is if you have workflow problem or document management problem. You have 1 workflow and a lot of documents, then might be you have DMS problem. You have 20 workflows and a lot of documents, then might be you have workflow problem. You can work with OpenKM embeded workflow engine or you can connect OpenKM with thirdparty applications like bonita. In a huge workflow scenario my suggestion should be choose the workflow engine what fits better your needs and then connect openkm with webservices API ( here openkm acts as an slave ).