The original Maestro MFZ-1 went on sale in 1976 as part of the TFC (Total Foot Control) series that included the equally legendary Parametric Filter, Stage Phaser and Fuzztain. With design duties ceded to Moog Music, innovation was always going to be high on the agenda; from the novel enclosure design (with illuminated, foot-operated control knobs and the whole pedal exterior acting as bypass switch - imagine a giant Mac mouse!), to the use of then space-age IC op-amps in the distortion circuit. It must have very much looked like the future back in the mid-70s (indeed, the op-amps + clipping diodes design went on to power countless classic overdrives), but the MFZ-1 was discontinued in 1978 just two years after it was introduced. Originals are therefore scarce and attendantly expensive.
Made to the same factory-specification as the original (same old skool Texas Instruments TL022 op-amp and the right mix of poly box and ceramic capacitors), the MuthaFuZza adds some modern conveniences like true bypass swiching, 9V DC jack (2.1mm Boss-style), wrapped up in a small pedal-board-friendly MXR-sized die-cast aluminium box and topped off with some very nice US-made fluted knobs. Battery also included. It's nice.
You may well be reading this because you've read that the MFZ-1 is an key weapon in Black Keys man Dan Auerbach's considerable fuzzy arsenal; well, if you like that brand of raw garage-bred blues-rock, step this way... The MuthaFuZza is a fuzz with a distinctly overdrive-y character, which means it handles chords (even fairly complex ones) extremely well and has a top-end sparkle and transparency on the treble strings that's good news for slide playing and quite unlike your typical 60s fuzz. Head on down to the lower registers and you'll find a truly beastly low-end response that'll handle a bass or baritone guitar especially well. Its unusually high (for a vintage design) input impedance means that it works well in front or beind a wah (where most vintage units will oscillate, eat your wah sweep or both). I've heard the MXR Distortion+ (another even earlier op-amp design) described as "a pissed off overdrive", well the MuthaFuzZa is a Distortion+ that badly wants to kick something in. Yow.