Paul,
I have the PA600 and Yamaha PSR750 and PSR950 keyboards on display. I do not stock the PA3X because most folks don't want to spend that kind of money for keyboards these days. That's why I'm excited to have the PA600s now. Most of the sounds, styles and features (including the pa3x chord sequencer) are included in the 600. Not a vocal harmonizer, but most of my customers don't use it, and a price point just over $1,000.00. Please come see me if you can't find a store with a PA3X and a PA600 side by side.