I operate the device as AP and had sat there without Manual within two minutes. Place setting on AP, SSID name and encryption set, DHCP client mode and channel width to 20MHz and off we went. Power consumption is 1.6 watts with! very nice low. Measured with a NZR SEM16 + and a HomeMatic Flowmeters.
Because I feel just about the AP functionality I have not looked at the other modes. The web interface is quite functional but kept for pure layman I think unsuitable. I use three wireless routers in the home with the same SSID and password on the three channels 1,6,11 and when a router is difficult to reach all the popular devices (smart phones / laptops) off to the next better router - without the user noted - around.
The range and speed is enough for my application where I wanted to supplying only one room with Wi-Fi. The 300Mbit are but illusory and I think only with the unusual 40MHz wide channels to achieve that will used by default and the box but you should not use the 2.4 GHz band.
I have the device only shortly, so I can not say anything about the long-term stability.