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For our first test, we used the map input function to choose a location on one of our favorite mountain roads, Highway 9 heading down to Santa Cruz from Skyline. On the SL550's system, we had to put the system into map-entry mode, then use the directional buttons to scroll the map south and west from our current position. The large screen helped us keep an idea of where we were scrolling, and the hard drive refreshed the map quickly so we didn't have to wait for it to redraw. The Nuvi 880 uses a touch screen, which we had to continually drag south and west. The smaller screen made this task more difficult, but it also refreshed quickly. The Mercedes-Benz system had the advantage here.

The route was easy, but the Mercedes-Benz calculated it just a little faster than the Nuvi 880 did. Both... // CNET Reviews

We've driven plenty of Mercedes-Benzes with this 5.5-liter V-8; since its development for the S-class it has become the standard big car engine for the company. In this application it puts out 382 horsepower at 6,000 rpm and 391 pound-feet of torque between 2,800 and 4,000 rpm. That power gets the SL550 to 60 mph in 5.1 seconds, according to Mercedes-Benz, with a top speed limited to 155 mph. We had no difficulty tapping that power and making the big roadster leap forward.

The engine is mated to Mercedes-Benz's now-standard seven-speed automatic transmission. The company has put a lot of fine-tuning into this transmission, making it perform as close to a manual as possible. A button at the top of the gate lets you choose Comfort, Sport, and Manual modes. As would be expected, Comfort is... // CNET Reviews