I had the KCNC brakes. They work ok but have more friction and need more lever pressure than Dura-ace brakes. Last year I was doing a lot of repeats of a local mountain with a lot of twisty descending and wound up with pain shooting up my left wrist. I need to be able to type to make a living, so I went back to the Dura-ace brakes.

Edit: I also have the skewers, they work fine.