2021 Mercedes-Benz S-Class vs 2021 BMW 3 Series

The 2021 BMW 3 Series returned to its traditional familial look, reminiscent of the classic E30 3 Series. However, the G20 3 Series appeared stuffy, with a big, oddly-shaped grille that seemed out of place on the smaller sedan. The design lacked distinctive features beyond the grille and headlights, which referenced older models' "halo" lights. Our test car, equipped with M 19-inch wheels and blue-painted brake calipers from the optional M Sport trim package, added some flair. The interior design was nice but marred by unimpressive materials, with plastic trim and fake-looking Ash wood. Leather upholstery was an optional extra, and the M heated steering wheel seemed out of place in the conservatively styled interior.

The 2021 Mercedes-Benz S-Class exterior styling didn't differ much from its predecessor, but it boasted a drag coefficient of 0.22, making it more aerodynamic than a Toyota Prius. The new S-Class was slightly larger in all dimensions, with a classic Mercedes hood ornament and grille adding a touch of ostentation. Standard 19-inch wheels, with optional 20-inch and 21-inch wheels, filled out the wheel wells nicely. The interior was designed around the infotainment touchscreen and digital instrument cluster, with a minimalist approach. Ambient lighting with 250 LED elements and 64 color options added a unique touch. Interior materials included Nappa leather, open-pore wood trim, and aluminum inlays, but the piano-black trim was prone to smudging and reflections.

The 2021 BMW 3 Series offered three powertrains: a 2.0-liter turbocharged four-cylinder engine in the base 330i, producing 255 horsepower and 295 pound-feet of torque; a 330e plug-in hybrid with a combined output of 288 hp and 310 lb-ft of torque; and a turbo inline-six in the M340i, producing 382 hp and 369 lb-ft. All powertrains were available with rear-wheel drive (RWD) or xDrive all-wheel drive (AWD) and an eight-speed automatic transmission. The M340i could accelerate from 0 to 60 mph in 4.2 seconds, while the base 330i took 5.6 seconds. The 330e matched the 330i's 0 to 60 mph time despite its extra weight. However, the 330e's transition from electric to gasoline power was clunky, and the driving experience lacked engagement. The chassis provided a comfortable ride and excellent handling, but the overall experience was underwhelming.

The 2021 Mercedes-Benz S-Class featured two powertrains: a 3.0-liter turbocharged inline-six engine in the S500 4Matic, producing 429 horsepower and 384 pound-feet of torque, and a 4.0-liter twin-turbo V8 in the S580 4Matic, producing 496 hp and 516 lb-ft of torque. Both versions used a nine-speed automatic transmission and included EQ Boost, a mild-hybrid system that added 21 hp and 184 lb-ft of torque for short bursts. The S500 accelerated from 0 to 60 mph in 4.8 seconds, while the S580 took 4.4 seconds. The S-Class featured standard air suspension and an optional E-Active Body Control suspension system. Rear-wheel steering reduced the turning circle by seven feet. The S580 was fast and comfortable, with precise steering and well-balanced handling in Sport and Sport+ driving modes.

The 2021 BMW 3 Series offered better-than-average rear headroom and above-average front headroom, though rear-seat legroom was average. The 3 Series lacked the shoulder room of some competitors, making it feel less spacious. Gasoline models had 17 cubic feet of cargo space, but the 330e plug-in hybrid's battery pack reduced it to 13.2 cubic feet. The trunk's long-and-narrow shape required an awkward reach to maximize space. The cockpit was well-designed, with a touchscreen positioned for easy reach and good outward visibility.

The 2021 Mercedes-Benz S-Class provided more front and rear headroom and rear legroom than its predecessor. It had more front headroom than competitors but the least front legroom. Shoulder room was segment-leading, contributing to a spacious feel. Cargo space increased to 12.9 cubic feet but remained less than other luxury sedans. Optional extras like power-adjustable rear seats could reduce cargo space. The front seats were highly adjustable, with heating, ventilation, and massage functions. The center console featured a large storage bin and a covered area with a wireless phone charger and cupholders. Rear-seat passengers had a large console/armrest with cupholders and climate controls. The optional Executive Line package added power-adjustable rear seats and four-zone climate control.

The 2021 BMW 3 Series came with the standard iDrive infotainment system, featuring an 8.8-inch touchscreen, Bluetooth, and two USB ports. Gasoline models included Apple CarPlay and Android Auto, while the 330e only had CarPlay. The optional Live Cockpit Professional system added a digital instrument cluster and navigation, with a head-up display (HUD) available. The infotainment system was responsive and easy to use, with multiple control options, including the iDrive controller, steering wheel controls, voice assistant, and gesture controls. Some features felt gimmicky, but the system provided flexibility.

The 2021 Mercedes-Benz S-Class featured a 12.3-inch digital instrument cluster and a 12.8-inch OLED central touchscreen, with wireless Apple CarPlay and Android Auto and six USB ports. An optional 30-speaker Burmester audio system and rear-seat infotainment setup with 11.6-inch touchscreens and a 7-inch tablet were available. The updated MBUX infotainment system had increased computing power and relied more on the touchscreen. Functions like climate control and seat massagers moved to the screen, but hard buttons remained for important functions. The augmented-reality HUD projected navigation arrows, which were helpful but sometimes distracting. The digital instrument cluster had beautiful graphics, but the steering-wheel touchpads were small and hard to use. Ambient lighting reacted to certain functions but seemed more like a gimmick. The S-Class allowed drivers to set up personal profiles with biometric or facial recognition, and rear-seat occupants could send navigation directions to the main screen.

The 2021 BMW 3 Series received a "Top Safety Pick" award from the IIHS, with top "Good" scores in all crash tests. However, headlight scores were mixed, and the optional Active Driving Assistant Professional driver-assist system scored lower than the base system in vehicle-to-pedestrian front-crash prevention. The NHTSA hadn't published safety ratings for the 2021 3 Series. Standard driver-assist features included forward-collision warning, automatic emergency braking, and lane-departure warning. The Driving Assistant Professional Package added adaptive cruise control, lane-keep assist, and automated lane centering, with a stop-and-go function and Extended Traffic Jam Assistant. A lower-level Driving Assistant Package added blind-spot monitoring and rear cross-traffic alert, and a parking-assist package with a 360-degree camera system and automated parking aid was also available.

The 2021 Mercedes-Benz S-Class hadn't been rated by the NHTSA or IIHS. It included a rear-passenger airbag and standard driver-assist features like adaptive cruise control, automated lane centering, automatic emergency braking, forward-collision warning, blind-spot monitoring, lane-keep assist, lane-change assist, traffic-sign recognition, a driver-attention monitor, and a 360-degree camera system. Mercedes claimed improvements in traffic-sign recognition, lane-keep assist, and the new steering wheel with capacitive sensors. The adaptive cruise control and lane-centering systems performed better than most competitors, handling highway curves and reacting smoothly to traffic changes.