I've played the synthesizer part of Little Shop of Horrors twice to date. The part calls for 3 keyboards (synth, electric piano, organ) stacked. The last two times, I was able to make do with 2 yamaha DX7 keyboards and it worked nicely. The sounds on those keyboards were "old' enough to get the effects we needed, etc etc.
For this run, (number 3 for me), I'm using a new keyboard and have been working on programming the settings etc for the past two nights. It's a more sophisticated keyboard then the DX7 and the sounds are more refined. But OH HOW I MISS the old DX7!!!! It made life so much easier. I'm toying with the idea of attempting to switch back to the old keyboards, we'll see after tonight.