I have made my decision. I will keep the PA900 and return the BK9. It was a tough choice, but I'm more comfortable with the Korg, and setup is quite a lot quicker and easier since it is totally self-contained.
I have set up about 50 entries in Songbook and have stumbled on a way to make organizing them much easier.
I also found a way to eliminate the need for at least one footswitch by assigned Break/fill to Dynamic Arranger function. In other words when I play pretty hard (adjustable) with my left hand, it triggers the Break/fill.
I have not recorded anything yet, but expect it to sound a little different from PA3X, but not much. I hope.
I'm waiting for Captain Russ to decide if he wants to add the BK9 to his arsenal before returning it.