Hi. I just finished building 2 bluesbreaker clones (from the pcb at tonepad.com, thanks Francisco).
I REALLY like this pedal. Perhaps more than a TS9. It is really open and transparent sounding IMO. Also, the distortion seems to vary more with how hard you are playing than a stock TS9. I suspect that's because of the "double diode" clipping arrangement that gives it twice the headroom of a TS9.
As an experiment I built one with 4 x 1N4148 diodes (ie standard) and another with 4 x 1N4004 diodes. The difference was VERY small, but I think I'd choose the 1N4148s next time. They seemed slightly smoother and less harsh.
cheers