Not the same sounds...Peep...
I was kinda juggling the 2 myself and realized they are not the same just ones a keyboard and the others a beatbox... Same type of concept just deferent macines though... RS7000 is less performance orientated so the sounds are not quite as good (out the box). With some programming they can be pretty good though. I think the sequncer has more tricks(knobs) and the drums might (might?) be different (better?). The Motif seems to have better overall sounds and concentrates more on the sounds and sound programming. I think the sequncer lacks a lot of the tricks and definatly the knobs of the RS7000. Basically the RS7000 is a "beat box" workstation (hiphop, techno,etc..)and the Motif is just a overall midi workstation. Sorta like a TRITON.
I think Yamaha kinda made the them to work together maybe????
At least that's what I've kinda come up with. Nothing I've said is offical though. Still juggling a few questions myself on the 2 myself.