[rifung]

This probably depends on where you live? I use Google Maps and when I was living in California it was completely awesome. However, having moved to Seattle recently, it definitely is not as reliable as it used to be. This might have to do with the roads here being much more complicated though.

[jschwartzi]

I've noticed that in downtown Seattle, the GPS has some difficulties maintaining a tight fix on your location. Couple that with how close together some of the roads are and you may find yourself teleporting from one avenue to the other as you move toward your destination.

It works great in suburbia, as expected.

[saraid216]

It's been explained to me that tall buildings play merry havoc with the GPS, but I haven't been able to test that out at all.