This is the lowest price for this month at $125.99. I bought mine last month from BestBuy at $189.99. This a good deal at $125.99. Cheers!
Picture is CTTO: Amazon
The difference between the old and the new is the packaging box. They're almost identical except of their price difference.
C7000-100NAS was listed on Amazon last June 18, 2015 and the newer Model: C7000-1AZNAS was listed last December 15, 2017.
Here is the link from Netgear community forum. Thank you.