Assigning 0 to 5 points for the realism of the first sounds, my score would be:
Tyros 5 / PA-4X
Piano: 3 / 5
Big Strings: 3 / 1,5
Full Pipe Organ: 5 / 4,5
Solo Violin: 3,5 / 5
Nylon Guitar: 5 / 5
I agree mostly with you... tough,
when it comes to strings on the Tyros 5, having the ensemble feature puts it 3 steps higher..
And there are even more impressive pipe organs in T5
The jazz violin on T5 has a jazzy sound to it, i prefer the celtic violin... having no classic SA2 violin is a minus indeed
However, you did not assign notes to the styles... because thats where i tought the PA4x shines compared to the standard Tyros styles (modding them however can add the desired realism)