My impression is that criticism, constructive or otherwise, of Yamaha products is not well received on the PSR Tutorial. There are Yamaha cheerleaders there.
I'm very careful of what I say on that site.
I still have two Yamaha keyboards and usually only post on that site if I need help with those keyboards.
PA 4X, S970, DGX650, JBL Eon One, Space Station V.3, Yamaha DXR10