Compare the2023 BMW 8 SeriesVS 2021 Mercedes S-Class Cabriolet

The 8 Series has a standard PostCrash iBrake, which automatically applies the brakes in the event of a crash to help prevent secondary collisions and prevent further injuries. The S-Class Cabriolet doesn’t offer a post collision braking system: in the event of a collision that triggers the airbags, more collisions are possible without the protection of airbags that may have already deployed.

The 8 Series offers all-wheel drive to maximize traction under poor conditions, especially in ice and snow. The S-Class Cabriolet doesn’t offer all-wheel drive.

Both the 8 Series and the S-Class Cabriolet have standard driver and passenger frontal airbags, front side-impact airbags, driver and front passenger knee airbags, side-impact head airbags, front seatbelt pretensioners, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, daytime running lights, lane departure warning systems, rearview cameras, driver alert monitors, available blind spot warning systems, rear parking sensors and rear cross-path warning.

The 8 Series’ corrosion warranty is 7 years longer than the S-Class Cabriolet’s (12 vs. 5 years).

BMW pays for scheduled maintenance on the 8 Series for 3 years and 36,000 miles. BMW will pay for oil changes, lubrication and any other required maintenance. Mercedes doesn’t pay scheduled maintenance for the S-Class Cabriolet.

A reliable vehicle saves its owner time, money and trouble. Nobody wants to be stranded or have to be without a vehicle while it’s being repaired. Consumer Reports rates the 8 Series’ reliability 26 points higher than the S-Class Cabriolet.

J.D. Power and Associates’ 2022 Initial Quality Study of new car owners surveyed provide the statistics that show that BMW vehicles are better in initial quality than Mercedes vehicles. J.D. Power ranks BMW above average in initial quality. With 24 more problems per 100 vehicles, Mercedes is rated below average.

J.D. Power and Associates’ 2022 survey of the owners of three-year-old vehicles provides the long-term dependability statistics that show that BMW vehicles are more reliable than Mercedes vehicles. J.D. Power ranks BMW above average in long-term dependability. With 5 more problems per 100 vehicles in the first three years of ownership, Mercedes is rated below average.

From surveys of all its subscribers, Consumer Reports’ January 2021 Auto Issue reports that BMW vehicles are more reliable than Mercedes vehicles. Consumer Reports ranks BMW 8 places higher in reliability than Mercedes.

The M850i’s standard 4.4 turbo V8 produces 60 more horsepower (523 vs. 463) and 37 lbs.-ft. more torque (553 vs. 516) than the S-Class Cabriolet’s 4.0 turbo V8.

On the EPA test cycle the 8 Series Convertible gets better mileage than the S-Class Cabriolet:

Regenerative brakes improve the 8 Series’ fuel efficiency by converting inertia back into energy instead of wasting it. The S-Class Cabriolet doesn’t offer a regenerative braking system.

All wheel drive, available in the 8 Series, provides the best traction for acceleration in wet, dry, and icy conditions. In corners, all wheel drive allows both outside wheels to provide power, balancing the car. This allows for better handling. The Mercedes S-Class Cabriolet is not available with all wheel drive.

The 8 Series’ launch control uses engine electronics to hold engine RPM’s precisely in order to provide the most stable and rapid acceleration possible, using all of the available traction. The S-Class Cabriolet doesn’t offer launch control.

For better stopping power the 8 Series’ front brake rotors are larger than those on the S-Class Cabriolet:

The 8 Series stops shorter than the S-Class Cabriolet:

The 8 Series’ standard 245/40R19 front and 275/35R19 rear tires provide better handling because they have a lower 40 series front and 35 series rear profile (height to width ratio) that provides a stiffer sidewall than the S 560 Cabriolet’s standard 45 series front and 40 series rear tires. The 8 Series’ optional 245/35R20 front and 275/30R20 rear tires have a lower 35 series front and 30 series rear profile than the S-Class Cabriolet’s optional 40 series front and 35 series rear tires.

The 8 Series M850i has active sway bars, which help keep it flat and controlled during cornering, but disconnect at lower speeds to smooth the ride and offer greater off-road suspension articulation. This helps keep the tires glued to the road on-road and off. The S-Class Cabriolet doesn’t offer an active sway bar system.

The M850i offers an available active suspension system, which counteracts cornering forces actively, limiting body roll and improving handling and stability. Mercedes doesn’t offer an active suspension on the S-Class Cabriolet.

The BMW 8 Series may be more efficient, handle and accelerate better because it weighs about 100 to 900 pounds less than the Mercedes S-Class Cabriolet.

The 8 Series is 6.9 inches shorter than the S-Class Cabriolet, making the 8 Series easier to handle, maneuver and park in tight spaces.

The front grille of the 8 Series uses electronically controlled shutters to close off airflow and reduce drag when less engine cooling is needed. This helps improve highway fuel economy. The S-Class Cabriolet doesn’t offer active grille shutters.

The 8 Series Convertible has a much larger trunk with its top down than the S-Class Cabriolet with its top down (12.4 vs. 6.9 cubic feet).

The 8 Series’ standard rear seats fold to accommodate long and bulky cargo. The S-Class Cabriolet doesn’t offer folding rear seats, only a ski pass-through.

J.D. Power and Associates surveys of service recipients show that BMW service is better than Mercedes. J.D. Power ranks BMW 7th in service department satisfaction (above the industry average). With a 17% lower rating, Mercedes is ranked 18th.

The 8 Series has a standard heated steering wheel to take the chill out of steering on extremely cold winter days before the car heater warms up. A heated steering wheel costs extra on the S-Class Cabriolet.