Bought a 38/720 case almost 2 years ago and finally put it to use today.  Now sparky motors are always great crowd pleasers but the wow factors goes up significantly as the size of the motor increases.  The I37DM is the biggest sparky I have flown to date and it did not disappoint!  Load and pround, off the rail on a big pillar of smoke and sparks with a really great echo off the treeline which got quite a few Ooohs and Aaahs from the crowd.  Arrow straight boost, just like a good tube fin rocket should.  Good drogue deploy at apogee, not drifting much up high but it appeared to catch some lift and move away from the line about half way down.  Good main chute at 500 feet and a nice landing in the field about a quarter mile away, easily winning the loingets recovery walk of the day.  After downloading the data from the Perfectflight MAWD you can easily see where the descent rate shallowed out during the recovery between about 1700 and 2200 feet.  Pretty cool.