I have used Bizagi Modeler which is part of Bizagi BMP Suite. This is great tool to create and describe different kind of processes and flows.
The biggest advantage what I have found very useful is automatic documentation creation in different formats like PDF, MS Word, etc. It saves a lot of time and effort, especially if additional corrections are required in existing process model and appropriate documentation must be updated as well.
Another good thing is that system warns you about some incorrect steps what you are trying to make during procecess modelling, it helps to keep integrity of model as such.
One minor issue could be related to restrictions for "gateway" used in process flow where gateway should be used either to split apart the flow or to merge together, both behaviours in the same gateway are not supported. This causes to use more gateways to handle specific cases thus process flow becomes more complicated.