Heated, 14-way powered front seats offer three memory settings each side, wide ranges of adjustment including seat cushion length and will frequently adjust headrest height automatically, which like many controls, you can manually override if you wish.   Metaphoric window switches that look like miniature replications of the seats are mounted on the doors to ensure they are easy to reach and understand.   On cars with power rear seats the driver may switch to control the seat behind him.   Meanwhile, the right rear passenger (the boss position) may control the right front seat for additional legroom.  

Drive Dynamic front seats offer ventilation, four varieties of massage, further adjustments for cushion and back sides, lumbar and shoulders.   Also, in what amounts to a sport seat with the comfort of a fine armchair, these seats can inflate side bolsters relevant to cornering load to hold you in place without being confining.   After using it, we aren't quite sold on this feature as we found it distracting when cornering, but it can be turned off; we like the massage feature.   Each seat is independently controlled and linked to the memory system.  

Visibility is very good for the driver, with a sloping hood, reasonable pillars, parking sensors at both ends, rear camera, bi-Xenon headlamps, fine-line defrosters, eight heated windshield washer jets, and rear headrests that drop out of sight at touch of a driver's button.  

The three-belt rear seat is huge and offers four AC vents, separate cabin and reading lamps, overhead lit vanity mirrors, and the same adjustable-color-and-intensity ambient lighting as the front hidden below the woodwork strips.   Behind the center armrest is another storage area and power side shades are optional.  

If your clients or kids are worth it a rear-seat upgrade package adds left/right rear climate control, plus heated and ventilated power-adjustable outboard seats and headrests.   This setup provides the utmost in comfort while maintaining five-passenger capability.   The entertainment package adds a height adjustable screen with video inputs behind each front headrest, video inputs and a DVD drive under the center rear seat, dual wireless headphones and an individual remote for each screen and the car's main audio system.  

Instruments provide standard data, the central speedometer a screen image; everything from navigation and radio to driver assists and mpg can be called up here via the steering wheel thumb buttons, and on AMG cars, additional engine info or a lap timer stopwatch.   With Night View engaged the screen shows an image of the view ahead with pedestrians highlighted, with speed along the bottom and warning lights superimposed around the periphery of the image.   Its central line of sight location and crisp imagery make this the best system of its type.  

The navigation screen, which can be angled toward driver or passenger and brightness adjusted separately from the instruments, is top center and well shaded.   Every operation done through the central controller shows here.  

A new option for 2010 and unique to the American market is Splitview.   This potentially marriage-saving device lets the driver see one full-size image (map, radio, seat control) while the passenger sees another (a movie with headphones or map if they're navigating) simultaneously on the single central screen.   Slide across the rear seat or walk behind the car and you'll be asking how did they do that.  

Controls are extensive.   Major driving controls are on the steering column, with a PRND shift stalk and upshift paddle on the right, downshift by the left hand (the paddles are close to the wheel with little finger space between).   On the left are stalks for cruise control, wheel tilt/telescope, and a busy one with signals/main beams/wipers/washers on it.   Suspension, parking and illumination controls are on the dash betwixt gauges and nav screen.   The eight-position light switch has off and automatic modes but even in off the headlights were often on in daylight, even after we consulted the six pages of owner's manual regarding the lights.  

Climate controls are arrayed across the center dash with true dual-zone operation, not merely independent temperatures.   The system also gives a choice of how airflow is layered and distributed through the cabin, lest you prefer room temperature or a constant direct flow of air over you.  

Mercedes-Benz dubs their control system COMAND and uses a round knob that rotates and moves in three dimensions, a mouse-shaped palm-rest that hides a 10-key pad within and four quick-access buttons across the front.   Through a series of quick-to-master menus and scrolls it controls hundreds of things, and while you can rotate the COMAND knob to change radio stations you can also use the keypad to punch the number directly.   The system is competitive with Audi's MMI, BMW's newest iteration of iDrive and Lexus mouse controller.  

Finishes are superb and mix contemporary like piano-black and ribbed brushed metal surfaces with more traditional wood and chrome.   Some of those high-gloss surfaces glare in the sun but those are single points because there are very few flat surfaces.   For details note how the center console opens from either side, the chrome lip on the strip of wood sweeping across the dash and doors, how the woodwork bends around the COMAND controls and console, and how window switches also handle the shades.   You know there has to be plastic in here somewhere but you never notice it, and the giveaway point on most cars, the pillar between the doors, is carpeted about a third of the way up and then covered in headliner material.   All S-Class have leather though there are different grades available, and more money usually brings an Alcantara headliner as well.  

S-Class comes with a 600-watt, 15-speaker harman/kardon Logic 7 surround sound system with a 6-DVD changer and memory card in the dash (auxiliary inputs are out of sight in the glovebox and run through the COMAND screen).   An analog clock rides center dash, on AMG models it is from watchmaker IWC Schaffhausen Ingenieur.  

Cabin storage includes a sizable pocket in each door, smaller pockets within the front door armrests, center console cupholders and bins, and a moderate-size glovebox.   The 20-cubic-foot trunk is ideally square-angled and tall, and therefore holds more cases and bags than many vehicles with greater listed capacity.   Some models have smaller bins underfloor above the spare tire, and it's worth noting that the S400 has the same trunk as the non-hybrid S-Classes.