If you use real time arranger controls in playing like sliders, knobs or switches, you'll missed them on the SD40 as Ketron minimized them to reduce the size and made it compact. I went back to MidJay Pro due to this reason. I found the MidJay Pro is better in arranger playing though it was primarily designed for multimedia player. Just my 2 cents.
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Jim
SD90,Korg I3, KMA Liverpool,TC Helicon Play Electric, Fender Sonoran Guitar, vArranger, Bose S1 Pros, Bose L1 Compact, Aiwa Exos-9