having owned the BK-9 it my opinion that the Yamaha is much better .

i was not a big fan of the Bk - 9 I also owned a G-70 and can say that unit was much better then BK-9

from what I can hear from demos it looks like SD-7 better as well.
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Genos, PSR S970, Fender Tele Amercian Deluxe Cherry sunburst , Cubase Pro 8 ,Yamaha A3M Acoustric ,Taylor 814, Ibenez Artcore Custom Tascam DP 32 Yamaha DXR 10, QSC K-12, K 12 Sub K 8 Sinn 945
2 Fender Expo line units .