ALWAYS second guess your GPS route! Visually look at the route it's taking you and see if it makes sense. I've been bitten more than once.
I haven't seen a newer GPS I like. They make them for clueless idiots and don't allow for changes from their limited and standard screen views. OK, rant off. :)
I like seeing an overhead map route with a large window for interstates, medium window for local roads and when I get near a turn or destination I'll zoom in so I don't overshoot. I also do many "what if's" looking for bypasses, shortcuts through towns, etc.
I'm old school still using a Garmin Street Pilot III Color AND I LIKE IT! It's fallen off the dash of many vehicles (bean bag mount) and still keeps on tickin'. I can see when sunrise / sunset is, current elevation, find waypoints by GPS coordinates, re-route, set via points for multiple stops . . . . OTOH the screen is small by today's standards, it updates slowly and the maps/restaurants/gas stations are grossly out of date. That's where the cell phone comes in. ;)
I'm not saying my old school GPS is the best (far from it). I just haven't found a new one I'm willing to plonk down big bucks for that I would be happy with. If the SPIII dies I just might find another on ebay, but this discussion gives me hope I can upgrade.
Best,
- bob