I really loved using the integrated FM transmitter to play MP3's over the car's stereo system (although I wished the transmitter was more powerful - finding a usable station in a large city is almost impossible, and you have to adjust it multiple times on a long road trip). When nuvi wanted to tell me about an up-coming maneuver, it politely paused the music, announced the next maneuver, and resumed playing the music. Using Bluetooth and the FM transmitter to transmit phone calls over the stereo was easy and made phone calls easy to hear.

The super-bright, white backlit screen would be reason enough to upgrade to the nuvi 680, especially given its newly reduced pricing. Add Bluetooth, traffic data, an MP3 player, photo viewer, travel guides, and long battery life, and you've got yourself one great GPS. At its core, navigation on the nuvi 680 is excellent. NAVTEQ mapping data and a sophisticated routing engine produced reliable and efficient routes. The nuvi could be built a little more solidly, but there's really very little to complain about - this is an excellent GPS.

The ability to view real-time gas pricing, movie times, and weather is a more useful feature than one might assume -- especially since they're all part of the same MSN subscription bundle.

If you already own a nuvi 660, it's probably not worth upgrading. If you're in the market for a new GPS, the nuvi 680 is a great GPS that offers first rate navigation, hands-free speakerphone, a built-in FM transmitter, real-time traffic, movie, weather, and gas pricing information, as well as text-to-speech and over 6 million Points of interest -- all in an easy to use package with a bright 4.3" wide display. As of this writing, you'd be hard pressed to find a better GPS.