One of the great things about guitar is that the tuning of the strings gives us all our open notes, and so tells us (or most of us) what is easiest to play. I suppose one measure of virtuosity could be not having to lean on open strings to make it easier. I play bar chords, and I love weird open chords that would be hard to get for most notes, but I'm certain some players get those chords at other places on the neck. I'd have to capo it.