The Parolin/KR bearings are nice. Instead of 3 set screws that use 3mm allen keys, they use 2 set screws that require 4mm allen keys. Ever since using them, I have not had an axle slip and do not need to use any type of threadlocker on the set screws.
I don’t really run them because I believe there a speed advantage, but more because they have removable seals and are easily cleaned and re-greased so I can get much longer service life out of them. I find when properly taken care of they spin quite free.