You make a good point, Fran...we usually appreciate most the sounds, styles, editing methods, and OS we have grown accustomed to...in your case Roland does the job.
Still, I was rather surprised you didn't jump for a BK-9, as the few reviews of it here on SZ seemed to be very positive.
Also, I am surprised it didn't appear to sell all that well, but maybe it's a slow starter like the G-70, which now appears to have more value to some players than it was when new.
I like Yamaha's OS a lot, because, although I like tweaking and editing, I don't want to spend too much time at it and want to be playing and recording instead. It is an easy, intuitive system made even easier by familiarity, as are most OS.
I'll feel a little better about the BK-9's worth when I hear that you have one, as I know you are very fussy with your arrangers, especially Roland, and you don't want gear that you don't make good use of.
Yamaha Tyros4, Yamaha MS-60S Powered Monitors(2), Yamaha CS-01, Yamaha TQ-5, Yamaha PSR-S775.