I also bought the Korg Pa1X Pro yesterday. I almost spend all day long playing it.
I still have my Ketron SD1 too like you. I am also pianist and I must say the Keyboard of SD1 and Pa1X are almost the same. My SD1 is 2 years old so of course not anymore same as new, but as I remember it was like the Korg one. (The best Keyboard Keys I ever played where the G800 ones).
I will try to record some MP3 and post them here sometimes.
The Pa1X crashed "freezed" only one time today. I always had this problems with every Keboard in Version 1.0 (Roland, Ketron, Korg,...). So I don't worry anymore ;-)