Look at the video content itself. The MZ2000 video's show arranger features. The MZ-X does not.
Sound for sound, Korg and Yamaha sound better at the $800 to $1100 price point.
The Mz-x is a fullfledged arranger.... Styles with 8 tracks and 4 variations, 2 intros, 2 endings, 4 fills, 2 breaks...
To make a real conclusion about the sound quallity, i need to get my hands on an mz-x and pkay them next to its comtenders...