I think the easiest thing to pin on it is... it's NOT a Yamaha, OR a Korg!

Roland go their own way. There's little in basic arranger operation the BK-9 can't do, but it does it as differently to those as they are to each other!

I admit, it don't come out the box as polished as a Yamaha (closer to a Korg in that regard), but the tools to sculpt it into what YOU like are all there. But instant gratification? Not unless you just LISTEN to it!