hi hellboy,
about a 60% improvement all over EXCEPT for the keybed and harmoniser(harmoniser still sounds great, just a few less options)...i will probably get around that by buying either one of the cheaper casio pianos with weighted action, or maybe look at the new yamaha n30....run this thing through a PA and it hums...no speakers on the the pa1x pro so i cant compare them, but on the pa800, the speakers are adequate without being brilliant..
it has EQ on all tracks now,no polyphony probs, better styles, better mix between variations and fills, i could go on...but just ask something so i can be more specific and in the new OS (due in june) an overall EQ, plus guitar mode and lots of other stuff i cant remember now...
cheers
dennis