The Equinox and WK6 are really miles apart. There are some of the same sounds found in both keyboards, but the engine and the way they work are really quite different. The Equinox is more a "synth" and the WK6 is more an "arranger". Many customers come in expecting to see styles and patterns in the equinox and once they don't they are disapointed. If you want to create everything from scratch, that is what the equinox is all about. The WK8 SE and the equinox pro both share the ProPiano1 voice set of 32 sounds now. I'm pretty sure than when the equinox first came out and I personally didn't like it's display and thought there weren't enough good acoustic instrument sounds, I was told by Generalmusic that the equinox has the same sound chip as the WK, but in my listening, I thought it didn't sound the same. I don't know if I'm wrong or right about this.
George Kaye