Bridgestone came to the club where I was a member at several years ago to do a ball-fitting. I didn't participate, but a guy I played with quite regularly did.
His ball of choice was the ProV1. So they set him up at the launch monitor... they've got this gizmo that detects spin rates, launch angle, the whole deal. So they tell him to hit his ProV, they give him like 10 swings with driver, do the average, etc. and then they compare that with one of their balls, I think it was the E6.
The net result, after the comparison and ball fitting, was that he was hitting the E6 about 9 yards further than the ProV1, most all of it due to spin. So he played a sleeve of the new E6 balls that was given to him for doing the fitting, and although he was hitting it further, he was not satisfied with the control around the greens.
Sometimes it's not necessarily about which ball goes further, but which ball you're most confident with the closer you get to the green.
On soft greens, for me, I don't really want an ultra soft ball. I guess that's why I like the 3-pc Srixon, because it performs pretty much the same regardless of the firmness of the greens. But it's an individual thing and not everyone is looking for the same things in a golf ball's performance.