One change from the 900 to the 1000 is they have dropped STS as far as I can tell. They are now using what they call "keyboard sets" instead. So that will be at least a minor learning curve if you are upgrading.
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Komplete Kontrol S61/Korg PA900/JBL 308P/Focusrite Clarett 2Pre/Band in a Box/Reaper/EZdrummer 3