This is my main source of instruments whenever i feel lazy or in need of a bit orchestration. Now granted, orchestral quality isn't like some pre-recorded sample libraries, but what it has is good enough to be used. It is great library of sounds to have offering large choices for any composer whom work is more about composition.
and though I did explore it when I first bought the keyboard I haven't really used it very much so I can't say much except it sounded great! I probably should investigate the AIR programs that came with the Advance 49 but always end up sidetracked to Kontakt libraries.