Well I have an R6300v1 that is absolutely horrible!! Worked great for almost a year now it drops lan connectivity constantly. I had the AC66R and returned it last week in anticipation of the AC68U. Never a Netgear again.
I was just using a R7000 as an example as to why to upgrade to an AC68U. I also returned my AC66 and ordered a AC68, since I was planning to setup an NAS.