Primary among changes for 2010 is the addition of the S400 Hybrid model. The first production hybrid with a lithium-ion battery the S400 maintains S-Class performance while significantly increasing fuel economy and lowering emissions without any of the typical hybrid compromises: Even when equipped as the S550 the S400 is the least expensive S-Class and has the same large trunk space. 

Another noteworthy item, optional on any S-Class is Splitview. This arrangement allows the driver and passenger to see a different image at the same time on the central dashboard screen. The driver may want to check maps and traffic while the passenger watches a movie rather than gridlock, and with Splitview both can. 

Other 2010 changes are smaller in scale and include things like front and rear lighting changes to make more use of LEDs. No detail escapes attention on the S-Class, and the same LED strip beneath the headlights (except base S400) shows white as a parking light and amber as a turn signal. 

At nearly 300 horsepower, the S400 is the least-powerful S-Class, yet capable of an electronically limited 130 mph. An S550 will reach 60 mph 1.8 seconds earlier in ideal conditions and offers all-wheel drive for less-ideal conditions, the S600 and S63 AMG almost a second quicker still (4.5 seconds), and the S65 AMG in 4.2 seconds. They're more powerful than the numbers suggest, as even approaching its 186-mph limiter the S65 is still pulling like a freight train. 

These cars handle remarkably well for big luxury sedans, composed, responsive and stable at any speed. The Airmatic air suspension system has both automatic and manual controls for ride height and firmness, transmissions bring multiple operating modes, and the braking system bred on the Autobahn's have massive reserves at more pedestrian American speeds. 

Inside, you are surrounded by wood, leather and finishes befitting an expensive car. Separate overhead lit vanity mirrors, ambient cabin lighting and multiple air vents characterize the base model's rear seat. Technophiles may revel in the best night vision system on the market, cruise control that will maintain following distance up to 125 mph or stop the car automatically, a smart man-machine interface, and seats that will massage, cool and self-inflate under lateral loads. 

The Mercedes S-Class competes with the Audi A8L, BMW 7 Series, and to a lesser extent the Lexus LS. The Mercedes S63 AMG matches up to Alpina BMW and the smaller but sportier-handling Maserati Quattroporte, Porsche Panamera and Aston-Martin Rapide, while the S65 makes a less-ostentatious (and faster accelerating) alternative to Bentley's Flying Spur Speed.