A nice used SX800 if within the budget might be the way to go. For starters, you are future proofed for quite a while. But the clincher might be the combination of the big touch screen and the Chord Sequencer, which makes a nice bonus for the one finger chord player… play the head once, hit play, then enjoy soloing over the changes without worrying about the left hand…
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An arranger is just a tool. What matters is what you build with it..!