You are right to in that samples on arrangers will not in some cases be as good as specialist virtual instruments or the real thing. Same is true of a Hammond sound, sax section, accordions, guitars...and so on.

But I would hardly say the attached Piano sound from the Audya sucks, Its a real nice vintage sounding Grand Piano that will more than satisfy most keyboardists. (if you want a vintage sounding piano of course)

No point in listening to it through computer speakers though