I would also read through the threads on rolandarranger.com. Especially Diki writes a lot of true things there, for example that the conventional saxophones (that are in the BK-7m as well) sound better than the SuperNatural one.
He also stresses the importance of the chord sequencer, which I strongly support; it is a main reason why I think I'll keep the BK-9. It opens many possibilities for your left hand.
The only things missing on the BK-9 are midiphrases/multipads, expendabillity of the soundset....
I saw a used one for sale on a dutchwebsite just last week for only €900, talk about a great deal, with prices of new instruments dropping to €1300..