I find this tool very helpful. The key UnBBayes improvement over other bayesian modeling tools is in support of Multi-entity bayesian modeling (MEBN) theory and the OWL ontology language and its probabilistic extension PR-OWL.
Bayesian Modeling can be looked at as a language for representing uncertain knowledge and relations among entities. The relation may be expressed logically and the uncertainty probabilistically. The MEBN theory is a formal integration of first order logic and probability theory.