I've got a friend with a S90 and one with a RD700. The RD pianos were far less than the S90 pianos in my opinion. The S90 has no floppy drive for playing back sequences. The RD has a basic sequencer, I think it was 4 tracks. The RD has very limited patch editing. The S90 has more editing capabilities. I think I would go S90 if you arleady have Roland JV or XP gear.