GPO takes the form of a performance-based library. It doesn't have samples of specific articulations, like staccato, but allows you to sculpt each articulation using midi continuous controllers and by varying velocity. The samples have been specifically adapted for this purpose. One advantage to this method is the very footprint of the library: you can load it very easily on a single machine (laptop!). Some articulations are harder to get than others of course. Horn rips, for example, are tough.