Kyoto:
I traded my Ref 2 Mk II (which I still think is an awesome product that I would be proud to own) for the Ref 3 several weeks ago. I had the chance to a/b them for about two hours in my home on my system using an sacd front end before I wrote the check. I thought that the Ref 3 was quieter, had greater dynamic range, and was more transparent. Also, in comparison, the Ref 2, while throwing a huge soundstage, sounded a little as if it had been processed through a phase shifter. The 3 did not have as big a soundstage, but now that I have racked up about 130 hours on the unit, that is coming along. Regarding the noise floor and dynamics, the Ref 3 was superior to the point that I had difficulty setting the two pre-amps at the same perceived volume. The difference was not unlike the blackness between notes on good sacd compared to redbook. Also, the 3 is not quite as warm and bloomy, but is tighter in the bass and cleaner top to bottom.
Although this sounds a little bit like the ARC promo, it is really my own thoughts developed primarily during the a/b session. Hope this was helpful to you. You really cannot go wrong with either pre-amp; both are great.
ROM