[Festus2]

I have 2 GPS units, one a Garmin the other a TomTom. Both have features that I like but my preference is the Garmin. The Garmin model in your link above certainly has many more features than mine but then again it costs more --- that would be the one I would want but not the one we need. If I were to buy any GPS, I would get one that has free, lifetime map and traffic upgrades and one that has a large screen.
We have found our GPS units very useful and we always have them with us.
Having said that, they do have limitations and can lead you astray - especially in areas where new construction, detours and other re-routing has recently taken place. Used in conjunction with a good map, they are a useful tool in navigating your way around strange places.
Keep in mind that the route they sometimes use is not always the best route -- it is often the shortest but not always practical. I can give you specific examples but they would apply only to our area and would not mean anything to you.
They are not foolproof but they certainly are handy not only for finding you way around but also for locating fuel stations, restaurants, shopping centers, hospitals, etc. while enroute.
If you do purchase one, don't leave it on your truck windshield when the vehicle is unattended. It is an invitation for someone to smash your windows and steal it. I even remove the GPS stick-on holder - that way, no one knows that you have a GPS in your vehicle.