My friends in Poland did a great comparisson of these 2 top boards



A 3 part video set that compares the single sounds can be found here.

http://keyszone.boards.net/thread/527/sound-comparisson-ketron-sd9-pa4x?page=1&scrollTo=888

but with arrangers its all about the styles. And i think the PA4x comes really close to the Ketron.