The worst part about the Korg harmonizer is that it only plays EXACTLY what notes you hold down with your fingers. If you use a simple arranger method of one or two fingers for your LH chords ... the harmonizer will only play those one or two notes held, and NOT the chord represented.
There also were no presets to speak of .... strictly a vocoder, and impossible to use with the RH unless the arranger was shifted to RH trigger.