I bought a Lowrance iwAY 500C on eBay for $500 and it has been very helpful. At first I was concerned about the distraction, but after a ride or two, that is not at all a problem. Of course I am a gadget freek; have Garmin GPS's in even my pickup.
As for the motorcycle, no need to stop, get out the map (who can remember 8 turns and that many road names over a 3 hours ride). Also, many times the GPS took me to some destination in my home county a different and much better route; of course the opposite is true also. In short, I don't leave home without one.