After buying the Digitech RP1000 and getting the best sounding MFX unit, I found that the harmonizer was terrible. I bought the Digitech GSP1101 and the sound is just as good. The harmonizer, however, is also bad but just makes it to usable status. Pay close attention to the wavering. The little unintentional distortion is not the problem and just my bad playing. That has not affected the harmonizer in other units. Bad playing is NOT the cause of the problem.