First things first. Always buy Garmin. They are reliable and work great. Nuvi is for on road use only, sucks off road, it just says your out in a field and its as useful as a $200 electronic cumpus. I would prefer the Garmin Rino series for off road use, it has a build in two way radio if your out of your car or don't have a CB, and the feature i love is the fact that if your buddies have a Rino, which mine do, it will display their location on your GPS as well. Its a great tool for hunting, not to mention if your off roading at pismo on a quad and get separated from your group, or on the trail, you can see how far ahead or behind you are from your buddies. The Rino now only comes in a color screen i believe, however you can find the black and white display ones on ebay still. Ebay is your friend...
My friend has and uses both the Nuvi 660 and the Rino 520. I don't know much about using the Rino on road though.
