Hi Jerry,
if you are interested, on my homepage you can read the 'pure technical' differences between the KN6X00 and the KN7000. See under the button 'keyboard'. Maybe this helps you for knowing some 'facts'.
Some hightlights are: the SD-card feature, the soundsystem, the polyphony, the organtabs and the new design (dustcover).
The KN6x000 is nevertheless an excellent keyboard and to my opinion for a good bargin, every penny on second hand market worth.
Best regards,
Cees