Dirtbike:
I got to thinking about your username. I don't imagine that you'd be particularly impressed with the Headshok if you come from an actual dirtbike background. Probably not enough travel for you. The Lefty on the other hand is pretty cool. My buddy has one on his Jeckel. He's been riding dirtbikes out in the desert since he hit puberty---going on three decades ago---so his standards regarding suspensions are pretty high. He love's the Lefty's ability to absorb bumps. Heck, he likes to demonstrate it's abilities by riding headlong into curbs, no unweighting the frontend or anything. He glides right over it every time. I wouldn't try that with my bike! And he wouldn't be happy with a Headshok.