I've had a problem with destroying headsets in my many years of riding. It hasn't been as issue with contamination but one of dimpling the races and flattening the balls. With a sealed cartridge headset you can just replace the bearing and all is good. With the Crank Bros. you can't do that, or am I missing something here? Just for a reference, I've been running a Chris King for over 2yrs on my dj bike that sees a lot of freeride, and it has never done me wrong.