CyberGene
It’s really hard to describe what exactly is wrong with the sound of Pianoteq. It’s always hard to talk about sound. But something that can point in the direction of what’s wrong is to use exaggeration: there has always been something that sounds like a Yamaha CP80. It’s very subtle, but if you somehow understand what exactly makes a Yamaha CP80 different than an acoustic piano sound, then that would be the trait/characteristic that’s making Pianoteq so ugly for me I can’t bear it.
Like this one: