I'm digging the Mad Professor SHO for low gain overdrive crunch and low gain leads. The tone has a nice piercing quality. Now I need a medium-to-high gain overdrive to stack with it for harder rock rhythms (think Black Keys, Zeppelin, etc.). I'll be stacking this second overdrive with the SHO for my maximum gain tone, so they gotta play nice together (without being too shrill since the SHO is already on the brighter side). Rig: Gibson w/ Z90 pickups and/or Telecaster > Fargen Blackbird w/ Weber Chicago speaker. Also use an Analogman Comprossor after the overdrives as a lead boost. I keep a ZVEX Super Hard On clone on at the end of the chain at all times to add a little sparkle to my tone. Anyone found a good match yet?