I can't pretend to know the answer to your question, but the differences in sound as described in the reviews (and the pro's and con's) are attributes I would associate with speakers, not receivers.
I did not see what speakers they used for the two reviews, but I have a tough time understanding how the 3060 with "Breathtaking Dynamics" became "Rivals offer greater Dynamics..." with the 3070.
However, since the 3060 is still available, why not save a few bucks and get last years model?
Is there a "gotta have" feature on the 3070?