Going back and checking my stats...
With the Rogue SZ I was hitting 40% FW and had an average drive of 279.
With the Epic Flash SZ I'm at 50% FW (and trending up) with an average of 286.
I think the main difference for me is the adjustable perimeter weight allowing me to dial things in a bit more. I've got the right side of the course basically eliminated now. The confidence I have now that I've found the right shaft makes driving the ball really, really fun.