thanks for the replies...I get that this isn't a traditional arranger. still, even with very limited onboard editing capabilities, it seems close to being a solution for some, if only because the drum sets of Motif lineage have sharper individual samples than those of the psr series.
and if it does read midi or .sty files, that will multiply its usefulness for some.

people use arrangers in all different ways, and despite the either/or tone of the above posts, there may be some who want a credible jazz waltz style or a polka AND decent hiphop/R&B/electronica styles. (which, in my opinion, are weak in the psrs). if the MM6, which doesn't offer that many onboard "patterns," can be expanded via a USB pen drive, that seems worth knowing.