This certainly sounds very good. I'm wondering if one can load and play the same organ twice, to give a better ensemble sound. I run GO on Windows XP with only 2gb RAM so I can't try it right now, but I plan to upgrade to a better computer (and maybe run GOLive or even a full Linux platform)
BTW I also listen to the organ on headphones (Sony MDR-V6). I have put a couple of Bass Shakers (affectionately known as Butt Shakers) in my bench. It adds a great effect to the low notes. Try it!