I have had my BK-9 now since they first came out. Have had a lot of fun with it and when I use it on gigs my audiences tell me they really like it because they can feel the rhythm of the songs. The more I experiment with it the more I tend to like the thing - kind of a love -hate relationship. The OS is a mountain to climb compared to other keyboards I have owned but eventually it seems to fall into place. I don't like the fact that a lot of "tweaking" is needed - even to get some of the voices right. Seems the Roland folks have never sat next to great instrument players. Oh well, maybe it is just me.
What has truly surprised me is the complete lack of interest in the BK-9. I have been trying to sell mine now for about 2 months on Cragslist, Ebay, and several forums and have yet to get a serious offer. Oh, if I wanted to sell it for HALF of what I paid for it I guess you could say I got serious offers.
Anyway, I play it about everyday but that will soon come to a halt - my Tyros 5 will be delivered on Wednesday. By the way, I actually agree with what Diki posted - it isn't that the BK-9 is TOTL, MOTL, Bad, or Good - it is just really different from the Korgs and Yamaha keyboard produced today. And, Diki has a great point - if you are a typical "ARRANGER" type player, like me, the BK-9 is probably not for you. If however, you do a lot of full keyboard playing with no split it has real options not found on other keyboards.
Deane