We bought this before our trip from Dallas, TX to Durango, CO. It did well to navigate us in a safe way and alert us to some road construction. We were able to tell it our height and length and weight, so it is supposed to navigate you only where you will "fit". I think it even avoided downtown Dallas on our return, which was not the case with our Garmin. I think with a PC you can access some additional features, which we haven't been able to figure out on our Mac. So far I love the screen size, the voice commands, and the display zooms to "as seen from the road" for exits and turns, which helps you tell where you are going, especially when there are options in front of you). We also like the warnings it gives for the changing speed limits. Texas seems to have a lot on the State Highways, as every 50 miles there is a new town with speed limits going from 70 to 35 as you get into the town. It can also warn you as you exceed the speed limit, or any speed you set.
Another benefit, no more disgruntled tone of voice saying, "Recalculating!" It does, of course, recalculate as you deviate from the path. But it doesn't fuss, like the Garmin.
We needed to make a fuel stop and pulled off the highway into a fuel station. Directly in front of us was a dirt road, heading off into the distance. The RVND immediately alerted us, "Warning! Your route will take you on dirt roads for about 15 miles." Yay! good to know!
Erika