Bryston SP2 - what's the improvement over 1.7?

The main difference between the SP 1.7 & 2.0 is a new digital chip- analogue pre amp is the same. Refer to Bryston site:

http://www.bryston.ca/BrystonSite05/pdfs/PREAmplifiers/SP1_7toSP2Upgrade.pdf

When listening to 2 channel playback do you feel there is a difference in sound quality?

I upgraded from the SP1 to the SP2, and the improvements are in the surround decoding. There is much more clarity and it is much closer to the original SP prototype that I got to listen to quite a few years ago.

Have you gotten any feedback on this subject? I am considering upgrading SP1 to SP2 and am looking for input from anyone who has compared the two.