I've got the Garmin V. And here is my story:
I like the routing feature, but don't leave home without a map. You've got to use some common sense with it.
When I was in North Carolina, we made a trip to Atlanta to see a buddy play the Falcons. On the way back the GPS beeps and says turn off (of the interstate). Yeah, me says, my wonderful machine has found me a shortcut. We drive for quite a while, and decide to dig out the map. One last glimpse at the GPS, and when I look up, we're heading right towards a dead-end...which just happened to be a LAKE! GPS showed it going through, but I don't think the 4Runner would have agreed.
The routing feature is nice if it's simple navigation, but it's not nice enough to justify losing the co-pilot! /ubbthreads/images/graemlins/laugh.gif