By now you must realize GPS is a good tool and that any tool may have a flaw. But GPS does work and when you use the tool the way it was designed it works well.
Just as an example ask anyone that owns a sailboat and cruises for years at a time. If a GPS can get you from Florida to Australia it should be able to get you from one city to another. Even our service men are using GPS to find their way Iraq and Afghanistan where they have never set foot before.