Diatonic is the working man’s pitch algorithm. Two voice ‘intelligent’ harmonizer, any key, 13 scales.  Pristine dual digital delays; 0 ms. to about 1.5 seconds.  Zero to infinite feedback, and a unique, musical routing based on the longer delay time.  PITCH MIX is in a position that allows delay trails and looping.

Four harmonies can get a little thick in a live scenario.  Sometimes that can be a good thing [Hammond B3 from Hell; jazzy synth, or massive power chords from one or two notes; riff rock layered lines].  I don’t think that the pitch tracking suffers from adding 2 more voices.  Like any pitch shifter, the formants can get a little ‘cartoon-y’ at the extremes.

Keep QuadraVox on your radar, though.  The Delay Grouping can be amazing under pedal control.  Scale-accurate arpeggios & ‘fingerpicking’, slapback 4 voice chords, and every delay rhythm in-between; all under foot control.  More for originals and experimentation than a bread ‘n’ butter covers set.  One practical technique is to take two harmonies, clone them, then spread those two doubled harmonies with short delay spacing and panning.  Powerful stuff.