It really depends on what you want to do with the sound, and what all your ribbon controller can be set to do.. When I had a Yamaha EX-7, I went nuts with my ribbon controller because I was able to control my custom sounds so much easier with it,,,,,, I know the Kurzweils use a ribbon for pitchbending, and to be honest I think that works quite well for pitchbending because you can pull of cool whammy effects when playing guitar sounds..
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GEAR: Yamaha MOXF-6, Casio MZX-500, Roland Juno-Di, M-Audio Venom, Roland RS-70, Yamaha PSR S700, M-Audio Axiom Pro-61 (Midi Controller). SOFTWARE: Mixcraft-7, PowerTracks Pro Audio 2013, Beat Thang Virtual, Dimension Le.