I run the Bridgestone EMax, and really like it for all types of riding. Haven't tried the Avon on the rear, so I can't make a comment on it. I do run one on the front, and have been very satisfied with it.
I have run DS on a couple of cruises before the R3R, but they didn't have near the lean angle of the R3. They are great for lasting a long time, but do handle differently. The only real negative I've seen was a picture posted by
@TriumPhil (I think), of a DS that had been ridden aggressively, and the letters were worn off the sidewalls. I don't think it's a common problem, but it was something that would always be on my mind if I rode one in the twisties.