George Kaye already said all.
I would compare MM6 with Juno-D and X50 in its feature and price range. Also it has 8-track sequencer that makes it workstation. For the price $600 it makes an attractive when prices of competing workstation start from $1000. The 213 "Arps" are actually phrases and for me the 6000 phrases of MOTIF XS are more attractive for the composition purposes.