wow that's a lot of cash to throw at a router and probably most of your devices can't even take advantage of 802.11ac at all. Unless you have some very very recent tablets/phones? also are you going long distances outside your house and want to be on wireless? that's really the advantage of 6 antennas.
The firmware on Netgear is very suspect, just gotta say I used to use Netgear a lot but even in the amazon reviews for the r8000, until a very recent firmware update, the router was having really really bad problems, both performance and heat issues.
I just got a small/medium business router from Cisco and i plug in devices that can be near the router and the others are fine all on 802.11n and it's a gigabit router. I'd say wait to see what other 802.11ac routers that come out and prices are a bit cheaper.