Hi Paolo,
I have had a chance , during my studies, to work with VSL and Noteability - espeacilly for its capability of sending and receiving MAX messages . It is a good program in terms of avangarde notation and not only.
The playback is also very tweakable as you mentioned ( both in terms of rithm / pitch) but I have found it a little buggy, when I actually tried to write complex scores and using many instruments. There are some caveats when you try to create crescendos / descresendos (CC 11, CC7 evntualy) with virtual many instruments in the background. Sometimes the program responds and sometimes not; writing p or f on the score, and using the velocity table ( by drawing) is not working all the time. I had two options : let the program to apply them , or you override it, but you cannot have dynamic written on the score...or it works for some time and crashes ..
Despite the fact that, both keyswitches and program changes (+ other cc data) do not appear on the print page, they can make a very agglomerated score when combined. I remember, by that time, that I coud not find a wat to make them invisible..
However, you can achieve very good results with this combination (VSL + Noteability), but you really need to try hard:). It is still primarily a notation program, despite its numerous playback capabilities. I would say that for solo instruments and electronics would work best. Something like : Solo Violin + MAX + Antescofo , or eventually in combinations with any other MAX patches of your like.
Please do also keep in mind that my above observations, are based on my work during 2013 - 2015 - so there are chances that the program to work way better at this point. By the way, I also paid for academic license for it, but now it's FREE !
Hope it helps,
Bogdan