I have a 12 and like it and I am planning on buying a 13 for the wife but she don't like the brake whine on my 12. So my ? is does the 13 have the whine or did the belt drive fix this? I do agree it is kind of annoying.
I felt that the belt drive whined less than my current 2012. The engineers said that it would make more noise in the beginning, then get quieter as it broke in.
The one I demo rode had 800+ miles on it and I did not notice any whine. My time on the sled was a lilittle over 2 hours everything seemed smooth and quiet.