Good bits of kit, though I personally find the 685s some of the ugliest boxes out there. I saw a pair in the flesh a few weeks ago and was astonished to see that they were as deep as they are; something the photos don't always show. The RS6 is a smart looking thing and highly rated. I'd suggest both deserve better amps, but the NADs are decent to start with.
If you want scale and dynamism, I'd go for the bigger speaker; for intricacies and detail or tight imaging, then the 685s.