And I'm not saying that aftermarket pulleys won't work well. But I have dealt with some drivetrains that just wouldn't have that nice smooth and quiet chain run, on all combos, with a non float pulley. When a repair is cost "challenging" and the guide pulley is worn out I will swap the two pulleys around. With the tension pulley nearly always being worn, but not anywhere near so floppy as the guide one, there is some sort of float but less lever over movement needed to attain the shift. While I do have some issues with the once 500 lb gorilla that is Shimano I have to respect their designs and goal of user acceptance. Andy