Hey RWC..... Here's my 2 cents....
There have been numerous chats/debates/discussions about the AT and NC but it really boils down to what you want to do with the bike. The NC and the AT are totally different machines.
I have a 2015 NC700DCT (22,000 miles so far) and have decided that it is PERFECT for what I do - which is mainly commuting. While I sometimes dream of having more power, a bigger front wheel, more off-road capabilities, and more DCT Sport modes, etc - I have absolutely ZERO need for any of those things. My NC provides for fun while going back and forth to work, gives me joy in the twisties, and hauls my wife and I around while averaging 73+mpg. I can sit in heavy traffic and not strain my left hand by holding a clutch lever and I can touch the ground with both feet. I added bags, a bigger windscreen, lowering links, and a better seat to make life more comfortable but I would have to do the same things to the AT.
So.... If you are looking for a completely capable commuter that can handle some gravel roads - the NC is hard to beat.
If you want a bike with a bunch of power and true off-road capabilities, the AT would probably suit you better.
Whichever way you go, Have fun - Go Ride
PS - I bought my bike brand new and, after all the things I've done to it, I am only in it around $8500... and it's paid off..