Some cars impress with technology. Others with design. But every now and then, a car lands in your driveway that feels like the product of a deeply experienced brand doing exactly what it does best, with absolute confidence. The Mercedes-Benz GLS 450d is one of the latter. And, with a long trip coming up, I could not have asked for a better chariot.
The GLS is Mercedes’ flagship SUV, a sort of S-Class for people who occasionally need to carry more humans, more dogs, or more lifestyle. In 450d form, it combines a mild-hybrid inline-six diesel with a focus on luxury in the traditional sense: no AMG badging, no hybrid, just torque, silence, and comfort.
You can tell a lot about a luxury car by how little it tries. The GLS uses fluid, organic lines to make the most of its considerable size, but without looking brash or bulky. There isn’t a single aggressive cut or crease on the bodywork. Instead, it boasts just broad surfaces, purposeful proportions, and plenty of presence. The same applies to the colour my loaner had: this spectacular green only shows its true hue every now and then, seeming black every other time.
Step inside and it becomes immediately clear: this is what Mercedes does best. The driving position is spot on: infinitely adjustable, comfortable, and flanked by the plushest leather. The tan upholstery in our test car elevated the ambience, letting the open-pore wood and exposed stitching really shine.
Within seconds of pressing the start button, the massage seats kicked in. Not as an option, but as part of what’s become a little ritual. Engine on, back kneaded, serenity engaged. I always give massage seats a good workout and these were no different, and the additional suede luxury pillows gave my bed a run for its money.
What stands out more than any one material or feature is the overall sense of ambience. This isn’t a cold, minimalist cabin trying to impress with slabs of glass. It’s warm, tactile, and inviting. And it makes you want to drive not because you need to go somewhere — but because this is a nice place to be in.
But, taking the GL name as far as it it will go, this is a spacious SUV, and a seven seater at that. Second row occupants enjoy plentiful space and adjustability (with power and heated seats), and a great luxury experience because of the massive sunroof, the generous ambient lighting and the warm sound system. While the second row doesn’t always return to its precise original position to preserve legroom for those in the third row, it’s genuinely useable space back there. No afterthoughts or contorted gymnastics required.
The GLS makes do with the previous generation of MBUX for its tech, and it is so, so much better for it. Not only does the smaller screen look better integrated to the dashboard, it also gives Mercedes more opportunities and surfaces to wow the owner with the quality of the finishing, buttons, and materials. I would much rather interact with the buttons that are available here, and see the mix between leather, alloys and wood than having to see a sea of shiny black plastic and screens everywhere. This is luxury done properly, and I wish we’d see more of this.
There’s a trackpad too, which is genuinely useful when you don’t want to smear fingerprints across everything. And when so many luxury cars are moving to full touch-only environments, the GLS feels like a masterclass in restraint. Everything you interact with feels high-quality and intentional. Not a single button feels cheap or generic.
Screens are easy to get around, and some of the menus that can be overwhelming have a set-and-forget nature to them so it becomes easier long term. Even the Burmeister audio system tuning interface is charming: it lets you adjust sound balance using a violin for treble and a double bass for low-end. It’s the kind of light-hearted detail that shows Mercedes understands its buyers.
Pop the bonnet and you’ll find a 3.0-litre inline-six diesel, paired with a mild hybrid system. Power outputs are healthy (243 kW and 700 Nm), but you wouldn’t know it from the driver’s seat unless you deliberately pushed it. This is a refined and isolated engine, with zero drama associated with it, even when leaned on. The great sound isolation lets only the best, warm tones invade the cabin when you’re going for it, and even before you come to a stop, it disappears into silence.
And the refinement continues. The start-stop system is genuinely astonishing. As soon as you lift from the brake, the engine restarts with such grace that if you weren’t watching the rev counter, you wouldn’t know it had cut out at all. In a diesel, that’s unheard of.
Around town, I averaged about 11.0L/100km. Once I stretched its legs on the motorway, that dropped to just 8.5L/100km — good enough for 1,060km from a single tank. That’s old-school diesel touring range, but with none of the rattle or roughness that used to come with it.
What stood out to me (and my numerous passengers) the most, aside from the comfort, was just how composed and settled the whole package feels. The GLS 450d doesn’t rush or shout, it simply glides. The air suspension smooths out even harsh hits, and there’s enough body control to keep things enjoyable, but when ultimate control becomes a requirement, you will be better served in Sport mode.
The gearbox is smooth and unobtrusive. It does have a lot of gears to work through, which means that if you want a gentle, progressive deceleration (say, for a roundabout), you’ll have to knock it down about six or seven times via the paddles. But that also means the engine is turning over at barely 1,600 RPM at 100km/h. You could be doing 140 and it would still feel like it was sipping fuel and taking a nap.
My time with this shed on wheels involved a roadtrip to Napier, and the return leg gave us a proper test: severe rain, thick fog, poor visibility. And this is where the GLS earned its badge. The confidence it gives you in poor conditions is incredible. The weight, the traction, the visibility, and the sheer stability all combine to turn what should’ve been a tense, fatiguing drive into something remarkably uneventful, in the best way possible.
And this was assisted by the driving assistances, which made both bumper to bumper traffic and open motorway driving even more relaxing. The adaptive cruise control shifts modes automatically depending on traffic and also road conditions. It will slow down not only for cars in front of you but also corners, with plenty of feedback so you know which mode is active. The integration of Apple Maps with the heads up display through CarPlay gives unobtrusive instructions, and the same applies to traffic sign warnings.
The GLS 450d is a reminder that true luxury isn’t about screen size, horsepower stats or lap times. It’s about how something makes you feel, and doesn’t beg for attention. Everything about it operates with quiet confidence, from the creamy drivetrain to the cabin materials to the way it carries itself down the road.
Yes, Mercedes-AMG builds jaw-dropping sports cars. And yes, EQS and EQE show they can play the EV game. But spend a week in the GLS, and you’ll quickly realise this is where the brand’s DNA really shines: large, luxurious, and deeply refined long-distance machines. It’s the kind of car that doesn’t just feel expensive, it feels considered, and comfortable in its own skin.
Yes, it’s expensive. But unlike so many SUVs that try to justify their price with gimmicks, the GLS earns it by doing the fundamentals better than almost anything else. I might have a sub-1-tonne sports car as my personal car, but masterclasses in hefty luxury like the GLS 450d make me grow fonder and fonder of this sit-back-and-relax formula, so I thank Mercedes-Benz for the amazing opportunity and thank you for reading this far!
