I got GPO4 last year and have been enjoying far more than I had expected. Gary seems to be one of the few guys who understands how important CC1 and CC11 messages are when it comes to expressivity in the samples. When I'm using Finale or Sibelius, a crescendo actually plays through on the GPO4 samples, unlike many other more expensive libraries that generally ignore those messages.
What I wanted to ask is whether Aria has only been added to Finale 2009/2010. I also occasionally use Sibelius 6 and I don't see the Aria player in that even though I notice the Sibelius Essentials plays through their Sibelius Player (not Kontakt any longer). Are those the older Garritan sounds?
To my ears, Finale 2010 makes the GPO4 and Garritan for finale 2010 sound better than in Sibelius 6. Could be my imagination but I don't think so. Also, Sibelius player does not have the World instruments that come packaged with Garritan for Finale 2010. The taiko and koto are really really nice sounding!