The following review is for a 2021 Model Year. There may be minor changes to current model you are looking at.

Introduction

The mildly outrageous Mercedes G-Class might get all the attention as the big Benz SUV, but the much more subtle GLS is just as opulent, if not quite as outspoken. 

For 2021, Mercedes has unveiled its own hot-rodded GLS63. Like other AMG productions, the GLS63 sports a 603-horsepower 4.0-liter twin-turbo V-8, performance exhaust, and all the requisite suspension upgrades to make this a genuine back-road and highway missile. 

The other big update is a new GLS600 Maybach variant. It sits atop the lineup as the most ritziest GLS to date, featuring copious leather and wood, power everything, and unique exterior styling that includes a hood ornament. The 4.0-liter AMG engine lives here as well, in 550-hp tune, in order to provide a level of thrust commensurate with the Maybach's $161,000 price tag. 

At the opposite end of the lineup and nearly a third of the price is the GLS450. It uses a 3.0-liter turbo-6 that makes 362 hp and 395 lb-ft of torque. A 9-speed automatic transmission is standard. Like every GLS, all-wheel drive is standard. 

The GLS580 uses the 4.0-liter twin-turbo V-8 found in the Maybach and AMG models, but power output is lower than either at 483 hp and 513 lb-ft of torque. The 9-speed automatic found in the turbo-6 backs up this engine as well. 

With this sort of power in this big an SUV, gas mileage is inevitably unimpressive. The turbo-6 is the thriftiest at 20 mpg city, 24 highway, and 21 combined. The V-8 models don't break 20 mpg, with the GLS63 the worst of the bunch at 14/18/16 mpg. 

The GLS hasn't been crash-tested, and the only standard bit of safety equipment is automatic emergency braking. Buyers will need to cough up some extra cash for adaptive cruise control, active lane control, a surround-view camera system, and an automatic lane-merge feature. 

Lineup

The GLS450 starts at $76,945. Standard features include synthetic leather upholstery, heated and cooled front seats, a power liftgate, and remote start. A 12.3-inch touchscreen with Apple CarPlay and Android Auto and a 13-speaker audio system are standard as well. 

The $99,795 GLS580 is the cheapest V-8 variant of the GLS. Besides its two extra cylinders, it adds leather upholstery and five-zone climate control. Don't expect much else over the base GLS, though. 

At $133,095, the new GLSG63 is next up on the pecking order. The brunt of the upcharge versus the GLS580 is attributable to the nearly 150 additional horsepower, but other features particular to the AMG include a unique grille, more aggressive fascias, 21-inch wheels, and nappa leather. All active-safety features are standard here as well. 

The pinnacle of the lineup is the $161,495 GLS600 Maybach. Once the domain of gussied-up S-Classes, the Maybach name is being repurposed for the most extravagant variant of the GLS. Standard luxuries include a 550-hp V-8, a four-seat cabin configuration, a rear console with heated and cooled cupholders and a wireless smartphone charger, 22-inch wheels, power rear seats with memory, soft-close doors, and a panoramic roof. 

Walkaround

The 2021 GLS breaks no new ground stylistically. Measuring nearly 205 inches long and riding a 123.4-inch wheelbase, it looks good in its base trim, but well-heeled buyers can go for the sporty or the old-money look depending on their preferences and the size of their checking account. 

The GLS63 manages to cultivate a more sinister attitude through deft use of trim and more aggressive bumpers; the Maybach goes old-school by laying on chrome and adding a hood ornament. Both models do a good job of highlighting their respective intentions. 

Interior

Mercedes's interior styling in the GLS is nothing short of exemplary, particularly on the upper trims. 

The eye first falls on the dual 12.3-inch screens-one the instrument cluster, the other the infotainment touchscreen-that seamlessly flow into each other, giving the impression Mercedes has installed a 24.6-inch screen. Keep looking around and details begin to appear, such as the finely knurled switchgear, perfectly stitched upholstery, and the near-total lack of exposed plastics or other low-rent surfaces. 

The front seats are heated and cooled on all models, and power adjustment is standard. They fit well, look properly luxurious, and are nicely supportive. The rear two rows are no less sumptuous. The rearmost row will even accommodate adults with relative ease. Those springing for the Maybach model lose that third row but gain an individualized second row that looks stolen out of a Learjet. 

Behind the third row, buyers will find 17.4 cubic feet of cargo space. That grows to about 48 cubes once the third row is folded and over 87 cubes when the second-row seats are dropped down. 

Driving Impression

Fast, smooth, silent-those are the words that come to mind in the first few moments of piloting a GLS. And yes, that includes the base 6-cylinder model, which is by no means short on power. The 362 hp of the twin-turbo inline-6 are strong enough to push three tons of Mercedes SUV to 60 mph in as little as 5.9 seconds. 

The fact that the 6-cylinder model can come off as so polished and befitting makes the V-8 models seem superfluous and unnecessary. And they are-but then what luxury isn't? The GLS580 isn't objectively better enough to merit its $25,000 upcharge over the six, but it oozes effortless power in such an indulgent way that it's hard to pass up if you can afford it. Big power everywhere, all the time-that's the GLS580. 

With 603 hp and a promised 0-60 mph time of just 3.6 seconds, the big AMG GLS SUV is a real barnstormer in every sense of the word, but the big 21-inch wheels and the firm dampers result in a stiff and unforgiving ride around town. 

On other models, ride quality is more appropriate for a top-tier Mercedes. The big 20- and 21-inch wheels hardly affect the ride quality except on the worst bumps. The standard air suspension immediately mitigates any rough patches of asphalt. The steering is heavy but devoid of feel. 

All powertrains get teams with a 48-volt mild-hybrid system that helps smooth out stop/start sequences and increases their frequency. How much it helps fuel economy is questionable, but we can report that the setup is hardly noticed from behind the wheel. 

Summary

The 2021 Mercedes-Benz GLS is another success for a brand that makes precious few mistakes. Other than its high price and lack of standard leather upholstery, there is little to dislike here and lots to rave about. We think that's particularly true of the base model, which delivers genuine panache at a price point much more palatable than every other GLS trim. 

 

-by Anthony Sophinos, with driving impressions from The Car Connection.