I am not overly impressed with the QS fletching however they did slightly improve my shot making. I too did not try grouping but I did manage 4 out of five Xs with 6 shots at 20 yards. I'm not too sure about the speed affectation but the trajectory seemed flatter. I shot them at 20,30 and 40 yards and I didn't see a huge need for any pin adjustment. I am going to chrono monday I will let you know.