GPO is an amazing library you coudnt ask for more!!
The only possible thing that would make make GPO better would to have a seperate software that generates CGI player's that accuratly play to the music you write.
Imagine you've just finished a Brass band fanfare or a full orchesral concerto, you play it and then generate a high quility video of CGI characters playing the insruments down to the correct valve fingers and even changing to mutes.
Untill Garritan uses this mad idea i'm happy with GPO.

Dan.