From what I gather after reading a bunch of scientific garblah, and checking out a few other things.
My best guess would be that the RGC won't have the ramp up time that I get from my RPM. It can burn at a much higher wattage and deliver a smooth hit faster because the airflow it creates cools the atomizer as you draw from it.
I could be wrong. Some of what I read was hard to understand. I'm not a physics major or anything. I'm ordering the RGC tank for my wife's fetch pro now. She's currently using RPM so I'll tryn' be sure to let you guys know if I can confirm here in a week or so.