I didn't get my mystery fuzz review in yet. Being a full time Dad in the summer sure sucks.
This was the pedal I was most interested in trying due to the fact that the only BJFE fuzz I ever owned was a CAF and with my rig at the time was just too bright! I'd actually like to try a BJFE CAF again and try a PPF as well though I am super pleased with the Bearfoot versions.
THe thing with the mystery (spell check keeps fixing Mystoury) fuzz, for me, was it didn't have the obvious personality of a CAF or PPF. Both of those fuzzes have a strong personality as well as many faces. They also work well through the whole range of the fuzz knob. They are not fussy about placement, pickup type or if the amp is clean or dirty.
The Mystoury Fuzz does not color the sound much for being a fuzz and I cant think of many other fuzzes I can say that about. Into a clean amp I found the Tone knob to be really useful through the whole range, but with vintage Strat style pickups I needed the Fuzz knob at least 80% of the way up. Even at 100% it was not a sustain machine. Into a dirty amp that has some natural sustain going the Mystoury Fuzz was exceptional! Especially with stock Strats and Teles and even more so with my orange Tele with a Novak paf sized WRHB in the neck and a hot T3 Zexcoil bridge pickup (which is rather nocaster-ish and no noise) which can get too dark with some Ge fuzz face type pedals.
One of my favorite uses for the Mystoury was to crank the volume and move the tone to the brightest setting > most any other dirt pedal as you would normally use it, or even the cranked amp, and adjust the fuzz knob to keep things under control. Or not! I wont say it could replace a treble booster, but for stacking with other Bearfoot or BJFE pedals it actually works better due to both the stability of the pedal and lack of noise most Ge treble boosters inject. I remember the first review of the Mystoury said it didn't have enough high end. I do not know if the pedal was tweaked again before I got it and the screws were glued in place so I couldn't see if there was a re-solder, so maybe Donner could chime in? I felt the tonal balance was close to perfect and if I could change one thing the option for more gain (for home practice volumes), even as a toggle switch or pre-gain knob, would be nice though at jam levels there was plenty of gain.
I changed the Voltages a bit from 7.5 - 18 and preferred 7.5 to 9 Volts the best as it had just enough sag to feel like you were interacting with the pedal with your fingers and pick. I knew I would only have it for a short amount of time as well as being new so maybe that is why I played it so much while it was here. With a dirty amp I think I used it so much due to the transparency. I have my 3 Swart amps tweaked to perfection with tubes and speakers so I am finding I am using pedals a bit less save for the time I can only play quietly. The Mystoury just fit in with what I am doing now though, strangely, I do not miss it like I did for the Purple Humper and my original Model H.
I agree with Hulakatt that it has a foot inside both the Fuzz Face camp and the Tonebender MKIII camp. The pedal I have that most closely resembles the Mystoury is a Lumpy's Tone Shop Led Bender (TB MKIII) with lower gain which I like enough to not sell, but it doesn't get used much either. Maybe in a few months when I build my LP Junior double cut and carved top LP (both with P-90s and stop bar bridge) I will be using the Led Bender or the Mystoury fuzz for often for the clarity and transparency.
Liked: Clarity and transparency, ability to resemble a treble booster when stacking, the space-age faux stainless steel enclosure and the lack of noise.
Want more of: It needs the ability to show a stronger personality with either a little TB MKI thrown in or the ability to get more extreme settings by itself.
Disliked: I would like unity volume to be closer to 9 - 9:30
That is about all I can think of at the moment. But I hope this stirs the pot a bit and it will be interested to see who has to have one now and what other peoples ideas are for tweaks.