George, do these Casios have either an "arranger hold" or "sync stop" function? In other words, is there a way to set them up so that when a style is playing and you lift your hand from the keys in the accompaniment section, the style stops; and when you play another chord, the style resumes?

Yamahas can do this by activating a setting called "sync stop" (you can even specify how long you have to hold the keys to "latch" a chord.) Roland and Korg also have a "sync stop" function in the style control section. In addition, Roland has a menu parameter called "Arranger Hold", and Korg has a "Memory" button right on the panel for this purpose.

I read the manual pretty thoroughly, and unless you activate it by pressing the "Syncrho / ending" button twice, it appears that Casio has omitted this important capability.

Which brings up another important question...

Do these boards have the ability to accept firmware updates? I wasn't into arrangers 10 years ago when the MZ-2000 made its debut. Can anyone say whether Casio supported that board with firmware updates to fix bugs, add features, etc.? Thanks!

Speaking of drawbars (sliders), did the zipper noise you heard come from the internal speakers or external amplification?

you are correct that there is only 3 levels for each slider in the drawbar mode. That is what Dave is hearing. The change from each level to the next. When using the sliders as a mixer for all other parts this is not the case.