AJ, thanks for your reply.

Tom, as you know already I like my XD3 a lot; the sound is cleaner compared with the SD1 (it looks like Ketron has improved the DSP), but of course the SD1 has more waveforms. The acoustic piano, for example, sounds more natural and rich, because the samples are longer with a natural decay.
Overall, the XD3 is a good unit, especially considering that I got it for 948 dollars (shipment and 20% tax included) from Synthplanet.
I think that this unit will have a great development in the future, in terms of sounds and other features. We'll see...
Yesterday I played the XD3 with my VA7, but today I tried the new 9000 pro instead; both work great, but of course playing from a 76 notes keyboard is much better.