Donny, They posted this on PSR Tutorial as well. The SX900 sounds good...but if you listen through headphones, the feed from the sx900 is stereo and the feed from the 975 is mono. Makes the comparison a little deceptive.
JM

Do you think they did that on purpose? I would rather hear an equal match up.

I really don't know. But, there does seem to be more presence and clarity coming from the SX900.
JM

I have no doubt that the comparison was slanted toward the SX900. Early on, the SX900 piano used a sustain pedal not present in the S975. Of coarse, the S975 was portrayed to be the poor stepchild left behind to facilitate a trade up state of mind.

sx900 in the demos sound like genos , i need to compare them and to find what is missing in sx900 , but if it is basic like genos and the price will be fine, it is a serious key

I saw this demo in passing a few days ago and it doesn't look like a great representation and comparison. The S975 sounds much much better than what's being portrayed here. When I get my SX900 I will still have the S975 so I'll hear for myself the true differences between the two but I am not expecting is to be that much of a gap.