Mikem....if the arp function is anything like the one in the MX49/61, it will be very useful.
and for modifying sound, the MX has 4 knobs that can be assigned to different perimeters....very effective for sweeps and delay effects, etc.
I'm actually really excited about these! hope the 770 and 970 show up sooner rather than later.
Tom, I agree with you. On my Yamaha Motif XF, my favorite thing to do is to create new performances using arps. There are 7,881 different arpeggios on board, and the combinations are (almost) endless.