Wazza,
I think as you, but not at all.
I think Yamaha sounds are ok. I don't see problem on it.
My question with Yamaha is about two things:
1. styles, too much mechanic, synthetic, repetitive drums, not full, not rich. It is as a litlle group is playing all styles, one after other. They don't make me happy playing. Korg styles are fuller, richer.

2. key feel is bad, bad, bad, baaaaaaaaad. It is the worse you can see.

By the rest, good sounds, good harmonizer, good support on the net.