If you know how to play into it (clean fretting, clean plucking/strumming), and set up your input signal just right, you can definitely get quite decent polyphonic pitch shifting (think full 6-string barre chords) with the Transpose on the QC. What is definitely still leaving much to be desired is the Pitch Correction block, which IS monophonic, and often screws up even on a monophonic source, in my experience so far.