"and go back to the full MIDI arranger section (which, to my ears at least, is not exactly the Ketron's strongest point"

i beg to differ

i think the Audy'a MIDI sounds phenomenal, better than Yamaha's, Korg's, Rolands, IMO, and i am picky when it comes to Midi

but to each his own,

with the Audya i get Audio and MIDI
i can use any combination of both

can't say that for the others can we?