It seems to be marketing speak for a higher TPI count (more supple) sidewall than their regular clincher. It's basically marketing speak. That said, I'm thinking about running the griffos as a general conditions tire. They're light and the tread is proven. I'm 195 and had perfectly good results this last season with my clinchers and had no flats even while running low pressures. I'm sure some of that were the rims, but that's another story...
I was able to roll my Maxxis Mudwrestlers at low pressure, but the most that happened was some grass getting stuck between the tire bead and rim.