Hi Erik, after all in all I now prefer number one. I would love to hear this with the App strings, which I have. I also own the KH library, but I noticed today after long sustains the KH library it loses it beauty, which I do not find in the App strings. In other words from a nice Vibrato to a non Vibrato, no matter if I adjusted the settings or not, which of course I did not find in his heavy vibrato samples, which carried a nice sustain. I have been back and forth with both libraries all day trying to make a comparision since I really had the time to really dig into them for hours on end for the first time..As of now I prefer the Vienna. KH does have a fantastic library also. It can be, I also do not control the controllers correct in Kontakt. But I still find the App strings, the Pro edtion Giga format I have,still to have more of a rich sound. My thoughts of course.Best, Joseph