I only watched the demo video ("Just the Two of Us") and it was pretty short. Jim has an excellent voice!

I didn't notice anything wrong with the chord changes in this short demo. There was a lot of reverb. It appears that Mr. Bannach plays "full keyboard" style, which could result in more frequent chord changes, and potentially some unintended chords on the off beats.

I'm strictly a left-hand chord guy. I'm also very picky about glitching and portamento during chord changes; these make the music sound "arrangerish." My own experience suggests that Korgs are better than the other brands when it comes to changing chords CLEANLY. Pre-Genos Yamahas can fumble around a lot, unless all of the keys are pressed within 0.02 seconds of each other (which is hard to do consistently.) I've often wondered whether this is the real reason why so many folks think Korg's vocal harmony is better-- because it's the recognized chord that drives the harmony. My $.02.