The PSR9000 and 9000Pro definately sound better than PSR2000. Because they use better quality stereo samples. PSR9000 and 9000Pro sound can consist of 8 tones per sound. The drums are stereo and you can hear the differenece very clearly. Although it's only on the live accoustic kits. The dance and techno kits suck on PSR9000 and 9000Pro ... they are same as in my aged PSR510.
I don't know if 9000 owners are using the sampling function, if they are not, then it's being wasted.

I have PSR2000 and TRITON, and they can sound very close to PA-80 when used together.

Anyone has PA-80 styles in midi format?