Hi Lucky,
maybe a phone call to the salesman, and he may be able to let you know what version os , the Pa800 was running. He just has to look at the screen while it's booting up.
If I remember correctly, Don M had an early version PA800. I think he was less than impressed. I immediately upgraded to 1.51 when I bought mine, so not sure what it sounded like prior.
Sound is subjective.

A couple of the forum members who upgraded from PA800 to PA2X, thought the PA2X sounded better. Haven't heard one, so can't really comment. I've mainly stuck with the PA800 because of the onboard speakers. I find them handy. I don't need the 76 keys as I have a digital piano I can midi it to.

Hopefully you can get to play a PA2X before you decide. Ideally be great if you can get to try both the Ketron & the Korg.

best wishes
Rikki