Yeah, I was a little suprised with this one.
You kind of have two choices here, voice for the boost sound (the last 10% of the drive pot), or voice for the rest of the turn.
Voicing for the boost was pretty easy, 2N3904, 2N5088 got a great fuzz tone, but the "clean" sound was less than inspiring - a bit flat and boring.
Getting a good clean sound was also pretty easy - 2N2222 were fine, but the fuzz boost gets splatty and gated.
Going with the BC108 got a great compromise, but substituting Q1 with the 104NU71 gives a subtle but noticeable improvement in clarity and sparkle, which it retains right through the volume range.
I've got lots of pedals for the Wall Of Fuzz sound, so I concentrated on the clean sound on this one. It's an absolute killer for all those "Nuggets" 60's garage punk rythmn guitar tones, and cleans up a muddy amp a treat.
The other thing that suprised me was how well it stacks after an overdrive or Tubescreamer - puts back all the clarity and definition the tube screamer removes.
And of course it's mind blowing with a Big Muff or Superfuzz.