In an attempt to find out why Synthplanet.com is listing the Ketron SD1 $500 cheaper than the older model X1, I found a link in their welcome page referring to the new Version 2.0 SD1 software release where it says: “In an attempt to solve the many problems of this instrument, Ketron has - at last - released a new system software version for use with the SD1”
Looks like Synthplanet people have a problem with the SD1 and that might be the reason for its low price!!
I think somebody from Ketron should look into it.

Maged