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2021 Mercedes-Benz GLS vs. 2021 Cadillac XT6: Which Is Better?

The Teutonic tank squares off against the Detroit deluxe in a battle of three-row SUVs. But does the 2021 Mercedes-Benz GLS have enough style, performance, and class to justify a $28,000 price difference over the 2021 Cadillac XT6? Which is better?

Quick Facts

  • Cadillac XT6 was brand-new for 2020.
  • Both fit seven full-size adults.
  • For 2021, the GLS gets the über-deluxe Maybach treatment.

2021 Mercedes-Benz GLS

2021 Mercedes-Benz GLS-ClassBase price: $76,495 / Read our 2021 Mercedes-Benz GLS-Class Review

What we like: Choice of engines; multiple driving modes; optional off-road package; luxurious interior; optional video navigation system.

What we would change: Looks are a bit conservative; enormously expensive, particularly with options; resale value is expected to be low.

Overview: Mercedes considers the 2021 GLS an S-Class luxury sedan with an SUV body. It’s hard to disagree with that assessment. Out of the gate, the 2021 Mercedes-Benz GLS comes with a 3.0-liter turbocharged V6 assisted by a mild hybrid that boosts power and torque. On top of that, there are increasingly powerful twin-turbo V8s, including a full-sport AMG version and an ultra-luxurious Maybach, although expect this one to top $200,000. Power is sent through a standard all-wheel-drive setup, making the GLS feel sure-footed and confident, and different drive modes range from Comfort to Sport to Eco. There is also an Off-Road package that we found to be quite effective in the Utah mountains. The GLS is not afraid to tow either, with a 7,700-pound rating.

Comfort inside is what’s expected from Mercedes, with rich leather and wood throughout, and ample seating for seven passengers (six with optional captain’s chairs in the second row). The Maybach drops passenger capacity to four or five, with the rear seats having features more akin to a private jet than an SUV. Technology is impressive, with two 12.3-inch displays front and center, the left offering the usual driving information and the right the infotainment, with Apple CarPlay and Android Auto standard, and an excellent Burmester stereo There are also some features that could only come from Mercedes-Benz, including a carwash setting that closes windows and folds the mirrors. There’s also an optional augment to the navigation system that adds video from two front cameras. Bear in mind, though, that in the Mercedes world, everything has its price, with the V8 upgrade from the base engine alone adding nearly $25,000 to the base price.

What’s new for 2021: Most significantly for 2021, Mercedes has added both the AMG GLS 63 performance variant and the next-level Maybach 600.  The AMG not only offers a higher-performance engine, but beefs up the brakes, suspension, throttle response and all the other sportier bits. The Maybach has only two rows of seating, and the rear rows have massage, recline, and climate control, as well as individual infotainment tablets and optional airplane-style folding tables. Four-zone climate control is new for 2021, as is the Parking Damage Detection feature. Standard for 2021 are also ventilated seats and 20-inch aluminum wheels.

Features and technology: There are four trims of the GLS, with the bottom two being the base GLS 450 and the GLS 580. The 450 has the turbocharged six-cylinder, with the 580 having the twin-turbo V8. Above that, the other two variants are almost in a separate class. The Mercedes-AMG GLS 63 has the twin-turbo V8 and lots of performance goodies, and the two-row Mercedes-Maybach 600 emphasizes luxury and pampering.

Standard features include a hands-free power tailgate, remote start, heated front seats, power-folding third-row seats, a surround-view camera system, and an air suspension. Also are quad-zone climate control and a system that can notify you remotely if your vehicle has been damaged. Infotainment consists of two 12.3-inch screens with Apple CarPlay/Android Auto integration, navigation, a Burmester audio system, and nine USB-C ports. Safety features include automatic emergency braking, blind-spot monitoring and a driver-attention monitor.

Options are plentiful and, as expected from Mercedes, packages can be expensive, including the $6,500 E-Active Body control that adjusts each wheel’s suspension individually for better ride and handling. There’s also an excellent optional Off-Road package. Another is Driver Assistance Plus,  which includes adaptive cruise control, lane-keeping assist, and stop-and-go assist. We love the augmented video navigation system that uses cameras to add direction markers and symbols and only costs an extra $300.

What does the future hold: Given that Mercedes clearly believes in the GLS, adding both AMG and Maybach variants for 2021, we can expect increased luxury and safety features as they become available. See 2021 Mercedes-Benz GLS-Class models for sale near you

2021 Cadillac XT6

2021 Cadillac XT6Base price: $48,990 / Read our 2021 Cadillac XT6 Review

What we like: Full-size third row; smooth ride; low price compared to the competition.

What we would change: Sharpen up the interior; needs more power; towing capacity.

Overview: Brand-new for 2020 and slotting between the two-row XT5 and gargantuan Escalade, the Cadillac XT6 returns for 2021 as a premium luxury crossover with three rows of seats for full-size adults. The base V6 has been replaced by a turbocharged 2.0-liter four-cylinder, which to our tastes is a bit underpowered, although there’s an upgrade 3.6-liter V6 in Premium and Luxury models. The base model comes with front-wheel drive, although there are three driving modes and all-wheel drive is optional. Sport mode offers a distinctly lively ride, but without a loss of comfort.

The exterior design follows that of its smaller siblings, the XT4 and XT5, and there are some well-placed luxury touches on the interior, including semi-aniline leather, rich woods, and soft-touch materials. It’s a very comfortable place to be, although to our minds, it feels a bit generic, without really distinguishing itself as a premium vehicle the way the Germans do. The 2021 Cadillac XT6 comes well equipped, and plenty of options are available, including the $4,900 Platinum package on upper-tier trims.

What’s new for 2021: The XT6 was brand new for 2020, so there are not a lot of changes for this year. Most significantly for 2021, last year’s 3.6-liter V6 is now the upgrade engine, with the base engine being a turbocharged 2.0-liter four-cylinder. It’s a bit underpowered, but returns 24 mpg combined. Wireless Apple CarPlay and Android Auto connectivity have also been added, and there are a new 20-inch wheel design for Sport models and a couple of  new paint colors.

Features and technology: For 2021, XT6 trim levels are increased from two to three, with the Luxury trim joining the Sport and Premium Luxury. Luxury and Premium Luxury models are offered with front-wheel drive and optional all-wheel drive, while the Sport has dual-clutch Sport Control all-wheel drive, continuous damping control, and faster steering.

The base XT6 comes with leather seating, heated 8-way power front seats, an 8-speaker Bose audio system, a heated steering wheel, and a power sunroof. Also included are a power-folding third-row seat, tri-zone climate controls, wireless charging, an 8-inch touchscreen with wireless Android Auto and Apple CarPlay integration, 20-inch wheels, and rain-sensing wipers. Driver assists include forward collision alert, pedestrian braking, low-speed forward automatic braking, front and rear park assist, rear cross-traffic alert, and blind-spot warning.

Options include ventilated front seats, heated second-row seats, captain’s chairs for the second row, a 360-degree camera, and a 14-speaker Bose audio system. On the top two trims, Cadillac also offers the $4,900 Platinum package, with Opus semi-aniline leather, a leather-wrapped console, a micro-suede headliner, and a performance suspension.

What does the future hold: Given its size and weight, we would like to see Cadillac drop the turbo four and return the V6 as the base engine, with possibly a higher-performance or even V variant available. See 2021 Cadillac XT6 models for sale near you

GLS vs. XT6: Strengths comparison

GLS Benefits: Standard all-wheel drive; tow rating; power; cargo capacity; luxury.

XT6 Benefits: Significantly lower starting price; better fuel economy; longer powertrain warranty.

GLS vs. XT6: Which is better?

If money were no object, the 2021 Mercedes-Benz GLS is truly an exquisite vehicle, with power, performance, and comfort to rival all comers. But in this case, there’s no denying a nearly $28,000 price differential, with the V8-powered GLS costing fully TWICE what Cadillac is asking for the XT6. But dollars to dollars, the 2021 Cadillac XT6 takes the win by a mile here. Just spring for the V6. See 2021 Mercedes-Benz GLS-Class models for sale near you or See 2021 Cadillac XT6 models for sale near you

2021 Mercedes-Benz GLS 2021 Cadillac XT6
Popular Powertrains
Engine 3.0-liter I6, turbocharged + electric motor 2.0-liter I4, turbocharged
Horsepower 362 hp @ 5500 rpm 237 hp @ 6700 rpm
Torque 369 lb-ft @ 1600 rpm 258 lb-ft @ 1500 rpm
Transmission Automatic, 9-Spd Automatic, 9-Spd
Fuel Economy 21 mpg (19 city, 23 hwy) 24 mpg (21 city, 27hwy)
Also Available 4.0-liter V8, twin-turbocharged; 4.0-liter V8, twin-turbocharged (AMG); 4.0-liter V8, twin-turbocharged (Maybach) 3.6-liter V6
Basic Warranty 4 years or 50,000 miles 4 years or 50,000 miles
Powertrain Warranty 4 years or 50,000 miles 6 years or 70,000 miles
NHTSA Overall Safety Rating n/a 4 Stars
Max Seating Capacity 7 7
Wheelbase 123.4 inches 112.7 inches
Overall Length 205.0 inches 198.5 inches
Width 79.9 inches 77.3 inches
Height 71.8 inches 69.9 inches
Turning Diameter 39.4 feet 39.1 feet
Headroom, Front 39.4 inches 39.8 inches
Headroom, Rear 40.2 inches 39.1 inches
Legroom, Front 40.3 inches 41.2 inches
Legroom, Rear 41.9 inches 39.1 inches
Shoulder Room, Front 59.3 inches 58.3 inches
Shoulder Room, Rear n/a 57.4 inches
EPA Passenger Volume n/a 149.9 cu. ft.
EPA Cargo Volume 84.7 cu. ft. 78.7 cu. ft.

Doug Lloyd
Doug Lloyd
Doug Lloyd is an author specializing in comparison tests. A veteran of the automotive press world, Doug started at Sports Car International and Vintage Motorsport magazines and has worked at both Porsche Panorama magazine and Doug is also a jazz piano player and a composer for television.

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