I'm on my 6th iPhone 3gs replacement do to a number of issues that I won't detail here. The point is I have had some experience with variations in the quality of the device. All of my other phones until this one had a serial number that started with an 8. The serial number of the newest replacement starts with a 5 so I assume it's a refurb. The point is my gps signal is extremely strong. I first noticed this when I was testing my phone in the parking garage after leaving the apple store. I got a signal immediately despite being in the middle of a covered garage. Then I tested it in the middle of my house at least 10 feet away from the nearest window and I get a signal within seconds. Mind you I am talking about the actual gps signal which pulsates not the cell triangulation. For comparison purposes I would have to stand outside for at least a minute to get a weak signal on my other phones. Most of the time I would have to reset the phone and turn off wifi. There is an extremely large range of variation with the iPhone's build quality and now that I got a phone that finally seems to work and it is probably a refurb.