Do you experience any latency when you use the B2 Four's Pitch Shift to transpose up or down a semitone? (Latency is a perceptible delay between when you pluck/pick a note, and when you hear the note.)
The different pitch shifter modules have different latency, but I'll mess with them more and give you a definitive answer about the tradeoffs with sound quality versus latency. Busy for next two days, but will try to test & respond soon.