Both have a lot to offer. Guitars are probably a little better overall on 950. BK9 organ is outstanding. Choir/pads are better on BK9.
Of course drums are better on BK9, except for the style Yamaha style that used audio drums.
I also preferred the bass lines on Roland.
I owned both and liked them both. What is NOT shown is lack of vocal processing/harmonizer, and lack of ability to display text files on Roland.
As far as pianos, I thought they were both "fine".
Another big plus for Roland is the facility for using their lightweight and affordable 6-switch foot controller. And more keys if you want/need them.