Are ZYXEL NBG6817 & Netgear R7800 still the best routers for WIFI coverage and stability?

In the UK, the Belkin rt3200 could be an alternative.

Hardware-wise, ipq807x would be the natural successor - but OpenWrt support is not quite in a usable shape, yet.

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Disclaimer: I have no personal experience with this device, performance is supposed to be good - wireless range apparently not quite on par.