Mike,
In my unscientific opinion, not the ball.
I believe it is in the knowledge and fitting of things. I launch the ball MUCh higher than when I played,
and hit that Maxfli further than I did when I wasn't fat and actually practiced.
My old Cleveland irons really do not carry much different, but my new Callaway Tour forged are about 4-5 yards longer
with PRO V1. With a NXT for instance, I carry that a bit further with my irons (2-5 yards than a ProV1), but have seen little
difference in carry with driver.
I do believe faster speeds get a better distance benefit with the ProV1x, but see a lot more distance control issues with the lower spinning balls for really good students. Not as much experience with the Taylor, Callaway balls. About the same with Bridgestones as the Titleists.