cody humphrey wrote a review of Magura USA Marta SL Mountain Bike Disc Brake on February 23, 2009
I love the way these beauties look! They're light as advertised, break well, great breaks in general. Pain in the ass to shim and adjust in my opinion. You have to use little spacers to get them set up just right with you rotor. Once they're dialed in, you're golden, though. I wish they's adapt some kind of system for adjustment similar to the Avid Juicys. That'd probably make them weigh more.
If you're a weight weenie, you can't go wrong with these! I've defaulted to the simplicity of Avids, but still have a set of these on my blinged out ride.