Note * I've found that my speedo is way off at the higher speeds. Traveling 115-117 on the VTX speedometer measured 105 on the GPS unit. The percent in difference varies with the speed.
I Added a Garmin Street Pilot III GPS to my VTX1800R due to the fact that we were taking longer road trips and longer stays in unfamiliar areas. Since installing this system I have never gotten lost...
I chose this particular model after talking with satisfied users. A few key features included independent battery source. This allows you to program the GPS waypoints without being connected to a external source. I found this feature extremely useful. Your able to take the unit into a restaurant, under a shady tree and program your route and destinations. Your not at the mercy of the VTX's battery source.