I purchased one from another member of this board when he upgraded. (Thanks again by the way) I used the speedometer on it in a truck that the speedometer was haywire. The mechanics set the computer in the truck to run 70 mph, but the Garmin said it was running 86mph. Enough of a difference to get you a serious ticket. Since then I have changed jobs and run a little further than just in town. The Garmin works fine, and I often use it even when I know where I am going. However, my preference has been the laptop with Microsofts mapping program in it, as I can see more of the picture and route my own way to my distination. Sometimes the GPS wants to take the scenic route, which isn't good when you are paying for a leased truck by the mile, especially with fuel prices like they are.
For those of you that travel to places you have never been, either is great but the GPS is easier to listen to than a laptop is to see while driving down the road.
David from jax