Zuki,
to be honest, I'm far from any expert as pianoman in any way, and now that the Pa4 is out of the house,
even before Pa5 came, I have to say that I cannot compare those two. (Even Genos is sold and gone, but G2 is on the way)
At Pa5 the first 5 pianos is Australian Grand, German Grand, Italian Grand, Japanese Grand and Classic Grand.
All sounds a bit different from eachother, but the two first is sharper and clearer than the rest, and Classic has lower 'volume' as is and less room / hall effect.
Sorry that I can't express myself better than this.
But one thing is pretty clear in my ears, the organs at Korg out of the box beats the Yamaha's with great margin. 😁🎶🎵