Is it true that the K2000 actually sounds slightly warmer & darker than the 2500, 2600 and 2661 ? Two different people I know have suggested this, and as they're so cheap now and the VAST engine is massive, it looks a great investment.
I have to say yes. I used to have a K2661 and found it sounded too clean for my tastes. I found a K2vx for such a great price I couldn't pass it up. I found that it sounds warmer and darker than the K2661. I cannot speak on the other models that I've never owned.
Go for a K2500R with KDFX (Super FX card) It is what I wanted the K2000 to be.
Same sound as K2000, but double polyphony and RAM. Better envelopes. MUCH better display. Better transposing of samples. Fantastic midicontroller, yes even as a rackunit! And when you add the KDFX, it takes the K2000 sound to another level.