QuinnLwrote a review of Shimano Dura-Ace BR-9100 Brake Calipers on September 28, 2017
Familiarity: I've put it through the wringer
After upgrading to full DA 9100, this is the only piece that left me disappointed. The rear brake squeals after finagling, toeing in to different degrees, re-adjusting, etc. etc. The same issue exists with multiple wheel sets, and never was a problem with 2 different versions of Ultegra brakes prior. Aside from the noise issue, they also do not stay centered after hard use, and I have to continue to unscrew the centering bolt and re-adjust. Maybe they are X% stiffer and brake X% more powerful than the previous version of DA, but the new design seems to have sacrificed other qualities unfortunately.