I've been thinking today that the difference is just as Dave says, more in playing technique.
I've been "fiddling"
with DSK Strings and the SI strings, and it seems there may be some workable sounds there.
I have a guitar TAB program that writes a MIDI file to go along with the TABs. It does hammer-ons, trems, bends, glis, etc., and I'm going to try and run one of these MIDI tracks through SI Strings.
I'll let you know what happens.