I have always avoided products from the company you not-so-subtly allude to.  They are nonresponsive to customer needs, and the printable output is too long and unwieldy.

I use HydroCAD, it is versatile and user-friendly.  A warning though, it is very hard to run a Modified Rational hydrograph.  I run it on another then input it as a Link.

I have Hydraflow Hydrographs loaded, but haven't had time to use it yet.  It looks similar to HydroCAD though, and is very competitively priced.

Remember: The Chinese ideogram for “crisis” is comprised of the characters for “danger” and “opportunity.”
-Steve

I use Hydraflow and it is very simple to learn, and does its job well.  It performs Rational and SCS Curve No methods, with four different methods of calculating the Time of Concentration (I use "user defined" for sink holes and "TR-55" for other watersheds).  Hydrographs may be plotted as graphs or tables of numbers.  It has a pond design wizard (that has never been of much use to me) and does pond routing calculations as well as ditch "reach" calculations. I've never had need to use its "Diversion" option, but make frequent use of hydrograph addition.  It has 12 different storm distributions and allows you to import your own. It is set up to calculate the 1,2,3,5,10,25,50 and 100-year storm (if you input rainfall intensity/volume information for each of these).

I use Hydraflow Hydrographs 2002 (version 7.0.0.18), which is not the latest version (2004).

Here's their website.

Although HydroCAD is designed primarily for use with the SCS/NRCS methodolgy, it can also be used with modified rational method.  You can enter the rainfall intensity and duration by hand, or setup an IDF file with your local data.  The real challenge is that rational method is more complex than it first appears, and is often misapplied.  For details see www.hydrocad.net/rational.htm or www.hydrocad.net

You can also post questions on the support page and get a quick reply www.hydrocad.net/support.htm