Hi Bill,
don’t know if I totally agree with you on that one, basically they’re rubbish in/ rubbish ,
rubbish out.
I got mine in the late 80’s when they first came out.
Sadly the majority of the recorded music discs for them, sounded like it was transferred from the old piano rolls, Hideous.
In the 10 years I had it , there was the rare disc, that was recorded by a real artist. They sounded great.
It was an amazing bit of equipment in it’s being able to record playing an acoustic piano with midi, plus being able to connect , synths, arrangers , whatever , via midi.

Can’t beleive Yamaha haven’t improved the quality of disks available? I didn’t keep up with the development after I had to sell mine. Seems strange they wouldn’t want to improved the quality of the songs.