They are a bit of a pain to get adjusted properly (compared to the BB7s I've also used), but they do have excellent stopping power once you get them dialed in. I have some on my Xtracycle, and even with me (220 lbs) plus the bike (~45 lbs) and 150 lbs of cargo, they stop on a dime. Well, maybe a nickel. But I can lay huge strips of rubber on either wheel -- if anything, my complaint would be that they are all too easy to lock up (not quite enough modulation). I'm using some old XTR levers and running full housing to both calipers.
Kill.cactus -- you mean the headset came loose, right? It would be pretty terrifying if the vibration made your head tube come loose...