The Good: The new blind-spot warning system on the 2009 Mercedes-Benz S550 advises when lanes to the side are occupied. Adaptive cruise control and night vision are two very high-tech features. Massage seats add greatly to comfort, while the Airmatic suspension smoothes out the road. The Bad: iPod integration doesn't show the music library on the car's LCD. Live traffic reporting doesn't warn of impending traffic jams. Poor fuel economy means a gas guzzler tax. The Bottom Line: If you can pay for the gas, the 2009 Mercedes-Benz S550 has many features to recommend it, and offers an incredibly comfortable ride, but don't expect it to play well with your personal electronics. Photo gallery:2009 Mercedes-Benz S550When Mercedes-Benz launched the model update for the 2007 S550, it created a car with cutting-edge technical features, including radar-based cruise control that could bring the car to a full stop and a night vision system. But major updates like this usually take five years in the automotive industry, which leaves the 2009 Mercedes-Benz S550 still very similar--besides a few feature add-ons--to that ground-breaking 2007 model. Although it is good that Mercedes-Benz recognizes the need for features such as live traffic reports and iPod integration to keep the S550 competitive, the manner in which they are implemented leaves a lot to be desired. On the road The first inkling of trouble with the 2009 Mercedes-Benz S550 came when we plugged an iPhone into a convenient connector in the glove box. Using the COMAND interface to select the audio source, the only option for the iPod was Aux, and nothing showed on the car's LCD. Knowing that Mercedes-Benz packs a lot of information on to its instrument panel displays, we chose the audio menu on the speedometer, and could see which song was currently playing. Using the speedometer display and the steering wheel button, you can browse and select music, but the interface is incredibly strained. We previously saw this type of Mercedes-Benz iPod integration with the 2008 ML550.This speedometer display is all you get for iPod integration.Leaving the iPod on the default shuffle setting, we headed out in the S550. The big car is gentle, providing an executive-class ride as it mutes not only external noise, but also the imperfections of the road. Where other cars slammed their passengers around from potholes and road construction, the S550 soaked up the bumps, partly because of the air suspension, which we left in Comfort mode. With generous leg room in back, the S550 had us wishing for a chauffer. But after discovering the massage seats, which are only for the driver and front passenger, we were content behind the wheel getting our tired backs pummeled. The seats also feature active bolsters, so that every time we turned the wheel, the side of the seat inflated briefly to keep us from sliding with the inertial forces. The seven-speed-automatic transmission acted like a perfect servant, remaining unobtrusive as it performed its duties, something an S-class buyer would expect. The big V-8 delivers its power easily, as well, moving the sedan effortlessly in normal driving circumstances, and showing it can pull when asked. A hard stomp on the gas pedal shoots the car forward, verifying Mercedes-Benz's claim of 5.4 seconds to 60 mph. On the freeway, we set the adaptive cruise control for 80 mph, not touching brake or gas pedals as the S550 matches speed with a car in the lane ahead going 72 mph. And here we discover a new tech trick Mercedes-Benz rolled out for the S-class--blind-spot warning. As cars ride in the blind spots to either side, a triangular red warning light appears in the side view mirror. At one point, hitting the turn signal while a car sits in the blind spot causes that red light to flash, and sounds a warning tone. Blind-spot warning is one our favorite safety features, and it's nice to see Mercedes-Benz got it right. The little red car icons on the map indicate a bad traffic jam.But just as we hit the peak of enjoyment from this drive, traffic starts to slow, until the S550 is crawling along at 10 mph. (And our foot is back on the pedals, as we don't trust the adaptive cruise control that much.) A glance at the navigation system map confirms that we have stumbled into a traffic jam, showing a bunch of red car icons all around our position. We think it would have been nice if the car had given us some warning, but Mercedes-Benz hasn't integrated the traffic feature well enough for that. We consider using the manual detour feature to find away around the jam, but realize that actually getting to our destination means we will have to get out of this ultracomfortable ride, so we decide to stick it out. In the cabin Understanding that a horde of visible buttons does not contribute to the notion of luxury, Mercedes-Benz keeps the controls in the cabin of the S550 spare. With its smart key, there is a big metal button to start the car, a neat row of metal studs for the climate controls, and the big metal knob for the COMAND interface, for choosing functions such as audio and navigation from the high-resolution LCD to the right of the instrument panel. Although easy to use, the COMAND interface can get cluttered with menus at times. This metal knob is the hardware portion of Mercedes-Benz's COMAND interface.Mercedes-Benz has been dragged, kicking and screaming, to Bluetooth, previously only allowing hands-free phone calling integrated with the car through special cradles designed for each compatible phone. Although it still has the cradle port, Mercedes-Benz tacked Bluetooth onto the S550, but the system failed to pair with the iPhone we used to test it. We noticed other phones had been registered in the S550's system, including one iPhone.The hard drive-based navigation system offers high-resolution maps that show building outlines in certain urban areas. When entering addresses, the COMAND system isn't as direct as a touch screen, but still works easily, helped along by good predictive entries. The system also performs quickly as it refreshes the map and calculates routes. Route guidance works well; we especially like how it shows which lane you should be in before a freeway intersection. But it doesn't offer text to speech. And, as we pointed out above, although it shows traffic incidents, it won't warn ahead of time about traffic jams on your route. We also mentioned the poor iPod integration. The S550 comes with a few other means of playing music, the most esoteric being a PC Card slot in the center dash, designed for MP3 tracks loaded onto flash memory. The six-disc in-dash changer reads both MP3 CDs and DVDs. The stereo receives both Sirius satellite and HD radio. Harmon Kardon provides the Logic 7 audio system, making music from these sources sound very good. With 14 speakers and 600 watts of amplification, its sound is very well-balanced, producing distinct highs and reasonable bass. Mid-ranges come out strong, making vocals easy to hear. Similar to other aspects of this car, the audio quality doesn't make itself obvious, merely coming through cleanly, without drama. Of the driver aids, the new blind-spot warning system is the most useful, providing ample warning about cars that might have sneaked into your blind spot. Adaptive cruise control is also quite nice, making long freeway cruises in moderate traffic effortless, at least as far as your feet are concerned. The night vision system makes it easier to see what's ahead of the car when it is dark out. Night vision is a truly remarkable feature, but of less utility. It can be activated only in the dark, and replaces the speedometer display with an enhanced black-and-white view out the front. Vehicle speed is displayed on a horizontal bar below the forward view. Night vision comes in handy when driving through dark forests or country side, as a glance down at the display lets you see much further ahead on the road than you can unaided. Under the hood With the launch of the S550 in 2005 came Mercedes-Benz's new 5.5-liter V-8, which has since seen service in many other of the company's models. The engine's size goes against the grain of today's more fuel efficient mindset, but it gets mitigated somewhat by the seven-speed-automatic transmission. Those higher gears go some ways toward increasing the miles per gallon at freeway speeds. The EPA rates the S550 at a dismal 14 mpg city and 22 mpg highway, opening it up for a gas guzzler tax. During our testing, with driving biased towards the freeway, we saw an average of 19.8 mpg. The Sport package on our test car included these AMG wheels.We pointed out the acceleration above, made possible by the engine's 382 horsepower and 391 pound-feet of torque. Even with the size of the S550, this engine never feels strained. The transmission has a stalk for putting it in drive and reverse, and there are paddle shifters on the steering wheel for manual shifting. The manual shift action is very good for an automatic, although it doesn't totally eliminate slushiness. According to Mercedes-Benz, the transmission adapts to the driver. Among our different drivers on staff, we didn't notice it change, but that may just prove it works exceptionally well. The Airmatic suspension is a tech feature we really like in this car. First of all, it lets you choose between comfort and sport settings, making a noticeable difference in ride quality. But even better, it does an excellent job of keeping the car from wallowing in corners by counteracting body roll, and that's saying a lot, given the size of this sedan. Although Airmatic suspension and paddle shifters for the transmission give the S550 some sporting characteristics, the steering is aimed much more toward the luxury side of things. The wheel turns too easily, and offers little feedback about the road. In sum The 2009 Mercedes-Benz S550 goes for a base price of $86,950, putting it squarely in luxury sedan territory. Our particular model came with about $20,000 worth of options, the most interesting from a tech standpoint being the Active Body Control system, for $3,960; the Premium package, adding the massage seats and night vision, for $4,990; and the adaptive cruise control package, which includes the blind-spot system, for $2,880. Fortunately, the navigation system and stereo come standard. Other options on our car, along with the $1,000 gas guzzler tax and $875 destination charge, brought our total up to $109,150. Although we found some issues with the S550's tech, it still earns a good rating for its cabin gadgets because of some of its driver aid features, such as the blind-spot warning system and night vision. The performance rating is buoyed by tricks like the Airmatic suspension, but dragged down by the fuel economy. It earns good marks for design, helped long by its stylish exterior, clean interior, and easy-to-use COMAND interface.