UnBBayes is a free and easy to use tool for Bayesian Networks. I am using it on my Master Thesis.
Just tried the newer (plugin based) version of unbBayes and glad to see the refinements. Ability to see the complete MTheory and do adjustments by dragging & resizing MFRag panels is cool.
I've been using UnBBayes for several years now, and it has come a long way. I am happy to have an implementation of MEBN. The changes over the past couple of years -- the GUI improvements, the plugin framework, the bug fixes have made it much better. I am really looking forward to seeing PR-OWL 2.0.
UnBBayes is a great framework for modeling with both traditional bayesian networks as well as provides an excellent way to model MEBN's. There has been a lot of improvements with the new version , especially with the plugin framework and GUI and with the other changes over the past months ,it is turning out to be a really great tool.