I recently had a week or so to get into the PA900, and got to know it..
Although I owned the BK5, but never tried a BK9 yet...but since I liked what the BK5 did..a lot, I am sure the BK9 will be on my want list.
I had some time on the PSR, but honestly, I can.t get pass that "lightning fast keybed"
So here is my rankings and why.
1: Korg PA900..Touchscreen, keyfeel,VH(although I think it needs updating), packed with features, but poor OS..
2: Roland BK9, site unseen, because the BK5 would have this slot in this list, and most likely the BK9 will easily jump to the top of my list, if all is confirmed when I play one.
3: Yamaha PSR s950, some good sounds, does not sound as realistic to me, even the Korg sounds "synthy".
My current ranking, with noted remarks ..