My friend has three Deco X55 in his home.  Excellent WiFi connectivity throughout the home, including in his attached garage.  This setup has worked perfectly for a year now.  Until recently, when he began having issues using his iPhone in the garage.  He can have full strength connectivity to "Living Room" satellite and surf the web endlessly.  Then, move to the garage where he still has great connectivity to Living Room.  He can use a Speedtest app to get >200 Mbps Internet.  However, the speed quickly declines until he drops all internet access.