I have a K5000S but haven't played with the K5000W. In addition to the additive synth voices, the "W" also has synth voices based on wavetable ROM, just like any other rompler based synth out there.It's like 2 synths in one. The "S" also has PCM waveforms, but these are mainly short loops or attack transients for the purpose of mixing with the additive voices to spice them up a bit.