Mercedes-Benz E400 vs BYD Sealion 8

What's the difference?

A convertible that doesn't feel like one when the roof is in place is no easy task to build, but it's one Merc's engineers have pulled off with the E400 4Matic Cabriolet. Effortless power, a tonne of technology and a comfy, leather-wrapped cabin all make Merc's drop-top E-Class a strong proposition.

There’s no denying the value the BYD Sealion 8 Premium offers as it packs a lot in for the price. Its efficiency and inoffensive looks add up to a good package and reflect what it does well. That said, the underwhelming driving experience and clunky media system are noticeable. Whether they're deal breakers is up to you.

Elegance. That's the word that springs to mind when you first clamp eyes on the E400 Cabriolet. While the Coupe version has a crouched-over sportiness about its exterior design, the convertible is all about big and boat-like proportions, especially with the fabric roof opened.

Like nearly all drop-tops, the E400 looks best with the cabin open to the elements, and the side profile especially paints a picture of well-heeled wafting, with only the AMG alloys and body styling hinting at the performance on offer under the bonnet.

Inside, expect perfectly executed modern luxury, with soft leather seats, touchpoints that melt under the fingers and a sprinkling of woodgrain trim. All of which feel like old-world luxury, nicely juxtaposed by the huge twin-screen display that dominates the dash.

The Sealion 8 is a big unit, and its design leans more towards soft and rounded than sharp. There’s a sense of restraint with its pillowy panels, smooth curves and flush door handles all contributing to a clean, almost clinical look.

The 21-inch wheels add a bit of presence, as does the full-width LED light bar with its braided design. But overall, it doesn’t try too hard to stand out. It’s inoffensive - clean and easy on the eye, but it stops short of having any sense of identity.

Inside, the cabin carries that same restrained approach. There’s black leather upholstery, some interesting geometric detailing through the panels and speaker grilles and a generous use of soft-touch materials throughout.

The large displays and panoramic sunroof help lift the space, giving it a premium feel, but more importantly, it’s just a comfortable, easy place to spend time. Which, for a family SUV, arguably matters more than anything else.

It's a two-door, four-seat convertible, so practicality isn't at the very top of its list of strengths.

That said, life is peachy for upfront riders, both of whom will travel in spacious luxury. There are two cupholders hidden beneath a woodgrain cover underneath the climate controls - also home to a power outlet - as well as a clever double-hinged central storage bin that can be opened by either the passenger or driver, and which opens to reveal two USB points.

There's room in the doors for bottles, too, and the entertainment system can be controlled via a touchpad controller mounted above the traditional click wheel - although, to be honest, using it is harder and more time consuming than simply pretending it doesn't exist.

Climbing into the back (and we mean climb - there are no rear doors) is made easier by the fact you can fold and slide the front seats automatically by pulling a lever mounted near the headrest. Once there, though, you'll find space is a little tighter, and you feel weirdly cocooned, owing to the huge raised tunnel that runs through the middle of the cabin, and the low roof line.

There are two cupholders that live in the space where the middle seat would normally go, and there's a little bottle-holder cubby to the left of both backseat riders. There are air vents back there, too, but no temperature controls.

The front doors are huge and really very heavy, requiring considerable heft to open them.

The boot space is predictably a little limited, with 385 litres on offer. There's also a little flip-down separator, which shows you how much room the roof will need to come down, reducing boot space to 310 litres. Speaking of which, the soft-top can be lowered in just 20 seconds, and at speeds up to 50km/h.

One practicality quirk, though. The front (and only) doors are huge and really very heavy, requiring considerable heft to open them, especially if you're parked on a slight angle. Honestly, I was reduced to kind of pushing them open with my foot at times.

Up front, storage and general usability are well thought out. There’s a handy shelf tucked underneath the centre console with two USB-C ports, while a tray above houses the fast wireless charging pad. You also get a sunglasses holder, two cupholders and decent-sized bottle holders in the doors, so it’s easy to keep things organised.

Seat comfort is a highlight, and the overall layout is clean and easy to live with, but the same can’t be said for the multimedia system. While the graphics are sharp and the touchscreen is responsive, functionality isn’t always its strong suit. Wireless Apple CarPlay and Android Auto are included, but CarPlay required reconnecting on every drive during testing and the digital radio and phone calls experienced noticeable signal dropouts. It’s the kind of friction that chips away at the day-to-day experience and starts to feel out of step with how polished the rest of the cabin is.

There’s also a heavy reliance on the screen for core functions. Climate control is integrated, which is fairly standard, but so too are things like headlight controls. It might suit those who are used to navigating everything through a screen, but needing to dig through menus to adjust something like auto high beam on the move feels like a step too far. Bring back buttons.

The second row is where the Sealion 8 really leans into its family-friendly brief. Space is generous, with enough width to comfortably accommodate three adults and the flat floor helps here too. There are three top tether points and two ISOFIX mounts, while charging is covered by a USB-A and USB-C port.

Amenities are a standout. The outboard seats mirror the front with heating, ventilation and massage functions, which quickly become a favourite, alongside dedicated climate controls, roof-mounted air vents and multiple cupholders. A set of sunshades would round things out nicely, but it’s otherwise a very accommodating space.

Access to the third row is less impressive. The manual slide and tilt mechanism feels a little heavy and fiddly to operate and the space itself is best reserved for kids. In practice, that means younger passengers will likely take the path of least resistance, as mine did and simply climb over the second row instead.

Amenities are fairly basic, with directional air vents and cupholders, but there’s no charging provision back there. You do, however, get two top tether points and ISOFIX mounts, which will be a plus for larger families.

Around the back, the boot is a practical, usable space with a wide opening and flat loading floor. With all three rows in place, there’s 270L on offer, which is enough for a few school bags or a grocery run, expanding to 960L with the third row folded. There’s no spare tyre, just a repair kit, which may be a consideration for regional drivers. A 12-volt socket and powered tailgate round things out in this grade.

The BYD Sealion 8 range is relatively straightforward, with two grades on offer and the base variant available with a choice of two drivetrains. For this review, we’re in the flagship Premium AWD, which is priced from $70,990 before on-road costs.

It lines up against the Chery Tiggo 9 Super Hybrid at $65,430 driveaway, the Kia Sorento GT-Line PHEV from $71,130 before on-roads, and the Mazda CX-80 P50e Azami, which stretches up to $87,950 before on-road costs.

On paper, the Sealion 8 Premium doesn’t quite undercut the Chery on price or match its claimed 170km (NEDC) electric-only range, but it’s not far off, with a still-impressive 152km (NEDC). And when you look at the broader package, it starts to make a fairly strong value argument, particularly against its other key rivals.

The 'Premium' badge isn’t just for show, either. Equipment is generous, with highlights including a fixed panoramic sunroof with an electric sunshade, leather-appointed upholstery, a heated steering wheel, and heated, ventilated and massaging seats not just in the front, but for the outboard seats in the second row as well - a feature that hasn’t gone unnoticed by my nine-year old.

Technology is a clear focus. There’s a 10.25-inch digital instrument cluster, a large 15.6-inch touchscreen multimedia system and a 26-inch augmented reality head-up display, alongside wireless Apple CarPlay and Android Auto, a 50W wireless charging pad and a 21-speaker DiSound audio system. BYD also includes 2GB of data per month for the first two years to support its 4G connectivity and over-the-air updates.

Practical touches round things out, with keyless entry and start, NFC card access and a digital key via the BYD app, a powered tailgate, vehicle-to-load (V2L) capability, rain-sensing wipers, sound insulation for the front doors and windscreen and three-zone climate control.

It's a fabulous engine, this twin-turbocharged V6 - even if it doesn't feel quite so lively in Cabriolet form as it does in the hardtop equivalents.

The 3.0-litre unit produces 245kW/480Nm, sending it to all four wheels via a nine-speed automatic transmission, linked to the standard 4Matic all-wheel drive system.

The BYD Sealion 8 Premium is all-wheel drive and pairs a 1.5-litre, four-cylinder, turbo-petrol engine with two electric motors, one on each axle. Combined outputs sit at a hefty 359kW and 675Nm, which comfortably out-muscles its key rivals.

Those figures do drop back to a more modest 110kW and 220Nm when running on the petrol engine alone.

Performance is strong for a large family SUV, with a claimed 0-100km/h sprint time of 4.9 seconds. You can toggle between pure EV and hybrid modes depending on the drive, which adds a layer of flexibility that suits short daily trips and longer highway runs.

Mercedes claims 7.4L/100km on the combined cycle (but you can expect to be pushing nine litres in real-world conditions), with emissions pegged at 170g per kilometre of CO2.

The 66-litre tank will only accepts 95RON fuel.

Charging is handled via a Type 2 CCS port, with support for up to 11kW on AC and up to 74kW on a DC fast charger. BYD claims a 30 to 80 per cent recharge can be done in as little as 20 minutes under ideal conditions.

The 35.6kWh lithium iron phosphate (LFP) battery is a standout, delivering a claimed electric-only driving range of 152km on the NEDC cycle. That figure is on the optimistic side compared to WLTP testing, but even with that in mind, it remains an impressive number for a plug-in hybrid of this size.

With a full battery, the combined fuel consumption is rated at just 1.0L/100km, translating to a theoretical driving range of over 1000km. Real-world results will vary depending on how often you’re able to charge and the type of driving you’re doing, but after a week that included a fair stretch of highway driving, my trip computer was showing 6.3L/100km. Overall, it’s a solid result, particularly for something with this level of performance.

Sure, the E400 Cabriolet can drive itself, but we’re equally pleased to note that it’s still a lot more fun handling the steering duties yourself.

And that is mostly due to that fabulous engine; quiet and effortless at city speeds, rorty and enthusiastic at pace, and genuinely angry with the drive setting switched to their most hardcore Sport+ mode.

We’ve already spent time in the sedan version, and while this Cabriolet is heavier (1935kg vs 1820kg) and slightly slower to 100km/h (5.5sec vs 5.2sec) it doesn’t immediately feel it behind the wheel, with a similar and satisfying lurch into the future when you plant your foot.

But hard charging is not what this car is about, and the E 400 is at its peachy best when rolling about the city or the ‘burbs with the top down, and the warm summer air washing through the cabin.

In its normal drive settings, the steering is light but engaged, and the ride on offer from the standard air suspension is outstanding, cosseting the cabin from all but the very worst road imperfections, while the torque from the V6 serves up effortless, unobtrusive acceleration.

With the roof up, Merc’s designers have done a stellar job of hiding the fact this thing is a convertible at all. It’s a solid-feeling cabin with the fabric roof fastened, and the cabin is quiet and free from wind noise.

On-road performance is where things become a bit of a mixed bag. There’s no denying the Sealion 8 Premium is quick and it leans more heavily into its EV character than many large plug-in hybrids. It’s quiet in hybrid mode and responsive off the mark, which makes it easy to keep pace in traffic and overtake when needed. For something of its size, it also does a good job of masking its weight on the move.

Regenerative braking is offered in two levels, but even the stronger setting feels fairly mild. The upside is smoother low-speed driving, with none of the abruptness you sometimes get in hybrids, and it does still recover a decent amount of energy, particularly on longer descents.

Where it falls short is in its overall dynamics. The steering and suspension are tuned for comfort, which results in a soft, slightly floaty feel on the road. It’s not unpleasant and around town it actually suits the car’s brief, but there’s a noticeable lack of feedback and control if you’re expecting something more composed.

Visibility and driver positioning also take some getting used to. The forward view is decent, but the pillars are quite thick and it can be difficult to find a driving position that doesn’t feel a little enclosed.

Judging the edges of the car isn’t always intuitive, and while the 360-degree camera is clear, its perspective can feel slightly off. Objects tend to appear much farther away than they are, which isn’t the most reassuring combination when you’re trying to manoeuvre in tighter spaces.

The BYD Sealion 8 is yet to be tested by ANCAP and therefore remains unrated at this stage. That said, it comes equipped with a comprehensive suite of safety features, along with nine airbags including side chest airbags for the front and second rows.

Standard equipment includes seatbelt reminders for all seating positions, front and rear parking sensors, driver attention monitoring and alert, tyre pressure monitoring, traffic sign recognition and autonomous emergency braking. It also features front and rear collision warning, blind-spot monitoring, rear and front cross-traffic alert and side exit assist.

On the road, however, some of the active safety systems are less polished in execution. The adaptive cruise control can feel abrupt when slowing down and slow to regain speed, while the steering assist can be overly reactive through corners. Lane keeping also lacks consistency, with the system not always engaging as expected.

For families, child seat provision is strong, with four ISOFIX anchor points and five top tether mounts across the cabin, along with child presence detection.

Expect the usual three-year, unlimited-kilometre warranty, with service intervals pegged at 12 months or 25,000km. Mercedes' capped-price servicing scheme limits maintenance costs to $2280 for the first three years of ownership.

BYD offers the Sealion 8 with a six-year/150,000km warranty and an eight-year or up to 160,000km battery warranty. Both terms are competitive for its class.

Service is recommended every 12 months/20,000km with each workshop visit averaging a solid $596 for the first five years (year four is $1360). Accessing a BYD service centre is fairly easy as there are around 70 centres nationwide now.

BYD recommends premium unleaded petrol (95RON) to be used for the Sealion 8.