People that call other people show off's do it because they can't do it themselves usually. It all has to do with the amount of fame and popularity. Nuno isn't as famous as other guitarists, and so I guess it can be seen as him trying to show what he can do. Vai and Satch, however, who are well established guitarists can be seen as show off's because they do the fast stuff over and over again when everyone knows they can do it.

I don't know.......just my 2¢