What is best software program for designing storm drainage networks?

Stormwater drainage systems are complex networks of gutters, inlets, and pipes. Analyzing these elements together is impossible for using traditional hand or spreadsheet calculations, and designing storm sewer components iteratively is too cumbersome, even for most hydraulic software.  StormCAD helps you plan and design your entire drainage system cost effectively and efficiently.

SSA, Mike, and PCSWMM for me are so far the best.