Most of the demos I posted here feature highlights of the BK-9 that are not found in the BK-7m.
- the SN-A piano you can hear in the Chopin Mazurka
- the SN-A trumpet, pipe organ and symphonic strings you can hear in the Händel piece
- the strings again you hear in the 'You only live twice' song (same as in SRX 04)
- the SN-A steel guitars that make the Gipsy Kings tune quite authentical.

The BK-7m pianos are good, too, but the differences with respect to strings, acoustic steel guitar, pipe organs (soft and full) and trumpet are substantial.

Personally I think the Gipsy Kings tune and the Alpine Folk tune 'Trumpet echo' are quite outstanding and sound as realistic as the BK-9 or any current arranger keyboard can get.
Yet, I can achieve roughly the same results if I midi a BK-7m to my Integra and edit thing accordingly.