I can only comment on the PA80 vocalizer vs the 2000. I disagree here. My 2k harmonizer has several more options available, but I don't rate the sound quality anywhere as good as my PA80's harmonizer. I also like that I can control the number of voices in real time on the PA80 via the amount of keys I press when making a chord with my left hand. I don't think the 2k has this, but I never delved too far as I realized quickly that its harmonizer just didn't sound as good ( at least with my voice it didn't ).

Maybe the 2100 has a better harmonizer. I didn't give that a test when I played one.

AJ