The major problem now in using ESP8266 for WiFi router routed application, is the IP address that is got to be written in the program ( say for Arduino) so it cannot be changed by a lame user.We have successfully overcome this by writing the vales of SSID & Password every time it faces a new wifi router on a serial terminal like (most user friendly is from Hackaday.--http://hackaday.io/project/3568-esp8266-test-program) .Run all the AT commands till you complete the SSID & Password and then remove the ESP and use it with any Arduino interface with program running from thereafter..