Hello Hans,
The two KB are quite different from your X1.
Starting with the styles, they are much simpler than the X1. I personally like it that way, since they fit a wide genere of music that way. Most of us 9000 owneres had to tweak the styles and the sounds a bit.
The X1 is more in your face, the 9000 is mellower. Sombody onces compared the sound this way: The X1 sounds like a life band, the 9000 sounds like a studio band.
Concerening the Saxes, some are better in the X1 some are better in the 9000. The same with the other sounds.
Of course it all comes down to taste.
Here is my recomandation: keep the X1 and get the 9000Pro (which I own) if you can.
The 9000Pro has much better key action, is a little lighter than the Psr-9000 and has 48MB of sound vs 36MB of sound in the Psr-9000. The grand piano is much better in the Pro.
As I said the styles are not very exciting at first, but very useful. Most of us have the Psr-2000 and CVP209 Styles, which load easily into the Pro. Some of them are quite a bit better than the 9000 styles. I'll be happy to share them with you, if you decide for he Pro.
Hope this Helps.
Let me know if you have more Quetions.
Oh yes Don't forget to listen to the 9000 first.
If you go under search, there are numerous posts on the comparison of the two.
Good luck
Eric
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Genos, PSR-S970, TC Helicon VoiceLive3, Mackie 802-VLZ3 Mixer, 2 Bose L1 Pro16, Electro-Voice ZXA1 Subwoofer