I would strongly encourage you to do a search on Gigapiano in this forum. You will find lots of feedback, both good and bad about this instrument. Bruce Richardson did an excellent and positively focused review on three of the popular pianos.
In a nutshell, there are \"only\" 31 groups of samples to make up the 88 keys so that for sure will cause coloration over ranges of the keyboard. You can open the file in GigaEditor to see how well your ear is discerning where the split points are. In addition, many have questioned the choice of microphone used to capture the instrument.
I have a 2 Sblives. One is running through an external D/A. There is no comparison in sound quality between the two. I do not know of Audigy\'s D/A quality.