I've had great luck with the wifi (except for switching between 4G and Wifi). Sometimes I take the dog for a walk and forget to turn the mobile data on. I've had the phone pickup my home (FIOS) internet signal from across the street and two houses down. Now my router is in the front of my house by a window but still a good range.
Switching to the cellular network from wifi thats another story
Switching to the cellular network from wifi thats another story