The Chord Sequencer and the Audio loop keys sold it to me.

Without those, I could have been OK with my G70's. But both of those bring a dimensionality to solo playing that I can't get from the G70 (or anything else in that price range and keybed size).

You generally find, each new arranger from the same manufacturer, only a few brand new styles. About 30 or so for the BK-9, and I doubt too many of them will be stuff I'll use. Most are in that small ballpark. Word is, though, that the BK-7 and G70 styles in it have been revoiced and balanced for the extra sounds, kits and MFX's in the BK-9, so there might be more to it than meets the eye.