To replace my Netgear 3500L in Tomato USB. The latter delivered me a maximum rate of 16 MB / s (128 Mb / s) with a cell at 1m with an Intel 6200 Wireless-N card or AC7260. With the RT-AC66U, and AC7260, WiFi AC and therefore Linux, I switched to 26 MB / s at 1m and always with Tomato Firmware USB again. Incidentally, the installation of USB Tomato is very simple and fast, and this firmware is even more complete and efficient than on my Netgear 3500L. It is also discrete (the LEDs are less pro-bright as the Netgear). PS: in original Asus firmware, it is as complete and simple enough to use after updating to the latest version. Just a little on limiting the transmission power and advanced features such as firewall or VPN. But for simple operation, it is the only router that I know that the original firmware is really good in the state.
I also tested the D-Link DIR-868L: grooooosse an empty box, a crappy firmware, limited and not at all ergonomic, and atrocious performance in the equivalent conditions (more than 8 MB / s throughput, less good that my simple Netgear Wifi N 3500L ...