Acceleration

S550	AWD S550	S600	S65	Class Average
8	8	9	10	7.3

S550's swift takeoffs support Mercedes' claim of 5.4 sec 0-60 mph. Highway-speed passing power particularly strong. No discernible difference with AWD S550. S600 stronger still, with abundant passing reserve. S65 is amazing, with abundant power always on tap. Transmission's part-throttle downshifts are quick, but full-throttle downshifts suffer a moment's delay. Both engines silky smooth. No opportunity to test S63.

Fuel Economy

S550	AWD S550	S600	S65	Class Average
4	4	3	3	3.9

Test S550 averaged 17.6 mpg in mostly highway driving. No opportunity to measure with other models. Premium-grade fuel is required for all models.

Ride Quality

S550	AWD S550	S600	S65	Class Average
10	10	10	10	8.4

Peerless blend of control, comfort. Suspension offers Sport and Comfort firmness settings. Sport makes ride slightly more taut, but at little sacrifice in comfort.

Steering/Handling/Braking

S550	AWD S550	S600	S65	Class Average
8	8	8	9	6.8

Poised and surprisingly sporty, considering size and heft. Uncanny ability to maintain composure in bumpy turns. Steering perfectly weighted. Brakes easily modulated. Distronic Plus cruise control accelerates, slows, even gently stops the car. But driver must apply brake in emergency-stop situations. Driver can regulate following distance, and Distronic Plus can be switched off, but fully trusting the system requires faith in technology.

Quietness

S550	AWD S550	S600	S65	Class Average
10	10	10	10	8.5

Aside from some mild thumping over sharp bumps, travel is serene, with little noise from road or wind. S550 V8 emits muted growl under full throttle, nearly silent otherwise. S600 and S65 V12s barely heard, even under full throttle.

Controls

S550	AWD S550	S600	S65	Class Average
8	8	8	8	7.4

Gauges large, clear. Controls and features in abundance; nearly all require some study to understand, and many divert driver's attention. Most climate functions handled by simple buttons, but COMAND system absorbs too many audio controls, complicating their use. It also governs daunting array of navigation, phone, seat, suspension, and cruise control adjustments. First-class materials, soft accent lighting create elegant interior ambiance.

Room/Comfort/Driver Seating (front)

S550	AWD S550	S600	S65	Class Average
10	10	10	10	8.9

Outstanding room, comfort. Seats offer fan ventilation, automatic-inflating side bolsters, relaxing massage function. Night View Assist clearly identifies otherwise unseen objects, but watching screen while driving can be slightly disorienting.

Room/Comfort (rear)

S550	AWD S550	S600	S65	Class Average
9	9	9	9	8

Head room tight for those over 6 ft tall. Leg room ample for two passengers, but seat width, high floor tunnel preclude comfortable three-abreast travel. Toe room restricted with front seats set far back. Supportive seat offers optional heat/ventilation and power recline with adjustable-length cushion.

Cargo Room

S550	AWD S550	S600	S65	Class Average
6	6	6	6	5.2

Trunk large, usefully shaped, nicely finished, and includes underfloor storage bin. Lid hinges dip into cargo area but are covered. Power trunklid closer available. No folding rear seatbacks or trunk pass-through. Interior storage space stingy.

Value within Class

S550	AWD S550	S600	S65	Class Average
10	10	4	3	5.7

The S-Class defines luxury motoring. Encompassing serenity and inspiring road manners are its hallmarks. Unfortunately, cars of this caliber also force the driver to interact with diversionary hi-tech features, many of which require far too many steps to adjust. In that regard, S-Class runs with the pack. Our Best Buy pick here is the S550. It delivers such high levels of performance and luxury that it is difficult to justify paying so much more for the other S-Class models.

Total Score

S550	AWD S550	S600	S65	Class Average
83	83	77	78	70.1

Scores for all Premium Large Cars

Low Score		61
Average Score		70
High Score		87