Can't testify to ultimate grip levels (I've only had them on for 100 or so miles, but they've helped make my notoriously hard-to-turn bike TL1000R) a pleasure in the corners.
I replaced Q2s with the Q3s and had BT-016s before the Q2s. Neither of those tires gave me the steering response of the Q3s. I truly feel that I can place my bike anywhere in a corner at any time. It's exhilarating. We'll see how long they last.