I build these, usually with a few modifications or customisations, to be more like the original than the re-issue. It's a terrific octave fuzz with a very handy clean blend, making it very versatile for everything from apocalyptic wall of noise, Hendrixy octave leads, to gritty and unique rhythm textures or broken amp sounds.
The clean blend and ample low end makes it a great fuzz for bassists too.
I have a stash of the rare NOS 2N9931 transistors, exactly like the originals had, I can either build them stock-though smaller, or with mods like the one pictured. It has a second stomp to turn the octave effect on or off. The toggle switch is for the two tone voicings, either very mid scooped, or boosted mids.