I think of good valves as fast, smooth and reliable. My belief is you should get a good set of valves on a good horn to begin with. Then, proper cleaning, oiling and care of not only the valves but the entire horn is crucial. That's what will keep them fast, smooth and reliable. I almost said my Benge has the best valves but I am biased because it is my favorite trumpet to play. I have a Getzen Eterna and Bach Strad whose valves are every bit as good as the Benge valves.