Some of the engineers use PC SWMM at work for flood line analysis and modelling. I saw today that Autodesk Storm and Sanitary Analysis it is available to download free for subscription subscribers.
PC SWMM and Autodesk SSA uses the EPA SWMM engine.
I have no idea which one is the best, But I would like to know what the differences are between the two. And if one is better that the other.