Perhaps it's user error, perhaps it's asking the device to do too much. But in the past month my Garmin has failed me 3 our of 5 times. First time, I was heading to an address in Natick, MA. I plugged in the street adress and off I was. The first problem was that Garmin took me through a ridiculous set of back-roads during rush hour instead of the major high-ways. Easily added 25 minutes to my trip. The next problem was that Garmin did not tell me the same street had a "North" and "South" variety (is this just a crazy Massacusetts phenomena?). Incredibly, the same block had a 19 North Main Street and a 19 South Main Street separated by only 100 feet. Of course I was led to the wrong building, having the unusual out-of-body experience of speaking to a co-worker on a cell phone, each of us equally convinced we were at 19 Main Street in Natick, left wondering whether the other was lying or we had entered a parallel universe.
Second and third times were similar challenges: Garmin taking me through a labrynthian series of side-streets and even ally-ways to get to my destination-- late. Now I won't claim to leave lots of extra time to make my out-of-office meetings, but it is reasonable for one to expect that a GPS device shouldn't ADD time to your trip.
Now perhaps you need to buy the higher-end version to get the intelligence needed to avoid such mistakes, but I guess I would expect more from a device like this-- otherwise what's the point?
By the way, last month there was another truck that crashed into a low bridge on Storrow Drive in Boston (no trucks are allowed on Storrow Drive due to the low bridges). The police quoted in the paper noted that this has become common in recent years and attributed this to nav devices-- the reason being that folks are busy listening to voice prompts from a GPS box instead of paying attention to road signs such as those warning trucks not to enter unpassable roads. Makes me wonder (again) how dependent we have become on machines, and how helpless we would be in they failed us. Or would we be better off? What do you think?