I just received one of these Parker H3L valves and I have to say that I'm impressed by the apparent quality of it. Admittedly, I haven't tried it yet, but the action "feels" much smoother and more refined than that of the Hoke Millimite 1300 series valve that I was originally planning to use in my upcoming build. Again, this isn't based on use, just tactile impression. I can't wait to see it in action.
If you had to identify, in one word, the reason why the human race has not achieved, and never will achieve, its full potential, that word would be "meetings." —Dave Barry