Let me start out by saying WOW. What a great bowling ball. I first threw mine on a 39' house shot and I hit the pocket from everywhere that I tried. In the past I haven't been the biggest pearl cover stock fan. But then Roto Grip came out with the last two pearls, the Critical Theory and now the Defiant Edge. I threw it on a variety of sport patterns from shorter to longer patterns, and with some small surface changes I could still use it. Even when I used a 2000 grit abralon, for the longer patterns, the ball started rolling earlier but it wasn't hard to get it through the fronts on the longer patterns. This ball is so clean through the fronts no matter what surface, and it retains so much energy for the mid-lane that it'll give you a strong and continous backend move. The surface changes that I used as slight as some of them were really made a difference. This ball is extremely impressive. Great job by everyone at ROTO GRIP. This Defiant Edge will give you the Edge!!!!!