Using Yún as a Wifi modem

Hi everyone,
i have quite a lot experience working with Arduino Uno, but now im planning to use Arduino yun to establish a wifi network and control 3 sensors of water flow wireless, but i can't decide the board i'll use on the sensors, Pro Mini with WiFi Shield or Fio with Xbee. can you please give me some advice and recomendations?

In my experience the wifi shield has some serious problems. Do not buy it! if you run the server example with no modifications "except what it needs to connect to internet" it will run fine for 12 minutes. After that the arduino will become unresponsive. If you run the client code only with no server code it will run longer, but it will become unresponsive within 3 weeks "best case scenario".

I was actually curious if I buy a yun shield to replace the wifi shield, does the yun have the same problem?

Suggest you look into the ESP8266. I haven't achieved it yet, but it will work with the Arduino IDE or NodeMCU.