Automotive Accessories: Affordable Navigation Units Compared - Gear Box

We examine four portable entry-level GPS units, all priced under $250, to see which one is best.Why spend big money on a factory navigation system when you can get a portable device for hundreds less? The question is becoming rhetorical. Portable navs may have smaller screens than the built-in competition, but just try moving that built-in from one car to another. The four nav systems below retail for less than $230 and have text-to-speech featur...