Career long MC-130 guy here, so no time at 650 kts, but...if I had it to do over again, I MAY have gone helo route. I was passing gas to MH-53s at 500' in Afghanistan back in 2001/2002 while they were hauling door-kickers to some bad guy's backyard. I remember thinking at the time I was in the wrong airframe! I would've loved to park in some dude's driveway, hand delivering America's most precise weapons. The CV-22 follow on would be pretty cool, too. Either way, to each his own.