950 has new drum kits, new vocal harmonizer, new distortion effects, new guitars, pianos and other new sounds. It also plays Tyros 4 styles very well. It is way easier to carry than Tyros and costs half as much. It has very good speakers.
The old sounds and styles may have the same names, but most of them are noticeably improved over the previous PSRs that I've heard.
I have not tried to do anything with the audio pads, but they seem to be missing some really great possibilities, and if past history is anything to go by, don't expect any major upgrades until a new model comes out.
Nothing earth-shattering, but a nice motl keyboard.
DonM