The Mercedes S-Class used to be the last word in luxury and, no matter how hard they tried, traditional rivals Audi and BMW just couldn’t get close. Then Porsche decided to muddy Mercedes’ waters and launch the Panamera.

Both cars offer a hybrid version, they have an almost diametrically opposed vision of what a luxury car should be, and there’s an intriguing battle in the making here. Porsche has stuck to the basic concept that every car it produced should have sporting aspirations, while Mercedes creates boardrooms on wheels that just happen to go fast.

So which makes the more compelling case when you really get down to it? Let’s have a closer look…

Mercedes S550e Plug-In Hybrid vs Porsche Panamera E-hybrid: Price

The Porsche weighs in at $99,600, while the Mercedes undercuts it by a few thousand at $96,600. It’s such a small margin and both cars are so expensive that it probably won’t be a dealbreaker either way, but there’s no getting round the fact that the Mercedes is cheaper.

The Mercedes S550e is priced aggressively for an S Class, but with both cars then you can send the final bill skywards if you really get fast and loose with the optional extras.

Mercedes S550e vs Porsche Panamera E-hybrid: Design

When the Panamera was first launched in 2009, it was universally hailed as the most heinously ugly car since the, well, Porsche Cayenne. The German marque created an iconic shape with the 911, but it just couldn’t seem to get the big cars right.

There’s an ongoing rumor that a Porsche executive sat in the back of the first prototype and demanded that the designers change the roofline, ruining the car’s look in the process. But Porsche brought us the second generation in 2016 and it’s a much more elegant car.

The roofline is lower, the nose isn’t as clumsy and it really looks like a 911 from the front. For such a big car, it has a sporting look and the box sections break up the sides well. The new car is just imposing enough, just classy enough and seriously aggressive.

The Mercedes used to be the last bastion of understated elegance and class. The new car? Not so much. The front end is stunning, but the profile is a clash of opposing angles and it just looks awkward. It’s a traditional sedan shape, with a short trunk that doesn’t quite fit.

It’s not ugly. It just looks wrong somehow and even the intricate and super bright LED lights can’t really save it.

So, and this has to go down as something of an upset, the Panamera E-hybrid wins the beauty contest.

Mercedes S550e vs Porsche Panamera E-hybrid: Power

For two radically different cars, the Mercedes and Porsche are surprisingly evenly matched in the power stakes. Both come with a V6 twin turbo powerplant and they’re dangerously close in terms of capacity.

The Porsche gets a 2.9-liter that pumps out 330bhp, while Mercedes has a 3-liter that’s good for 329bhp. The Porsche, though, gets a 100kW (136bhp) electric motor, while Mercedes opted for an 85kW (114bhp) electric motor that is packaged within the seven-speed gearbox. So the Porsche has the edge, with 462bhp compared the S-Class’s 436bhp, but all of it comes from the Panamera’s additional electric pull.

Porsche wins the torque war, too, with 516lb/ft compared to the Mercedes, which gets 479lb/ft. It’s not a massive difference, but it’s enough to give Porsche a convincing win here.

Mercedes S550e Plug-In Hybrid vs Porsche Panamera E-Hybrid: Acceleration

The Porsche has more power, a four-wheel-drive layout and it’s tuned for performance, so it was always going to dominate this one. The Panamera E-Hybrid 0-60mph time of 4.4s leaves the Mercedes trailing in its wake. The S Class just isn’t built for pure speed and it limps past the 60mph mark in 5.2s. That just isn’t good enough in this company.

The Porsche’s extra gear means it is better equipped for the straightline dash and it should just keep pulling away from the big Mercedes until it finally hits its top speed of 172mph. The Mercedes will be a speck in the mirror by the time it runs into its electronic limiter at 155mph.

So this one isn’t even a contest. Porsche wins by a country mile.

Mercedes S550e Plug-In Hybrid vs Porsche Panamera E-Hybrid: Handling

We’re starting to feel sorry for Mercedes here, but the truth is that it was never going to stand a chance when it comes to handling. This is Porsche’s stronghold.

Porsche took a backwards concept, the rear-engined 911, and turned it into arguably the greatest sportscar of all time. So even though the Panamera weighs in at 4,960lb, the marque has a wealth of tricks to make it hug the apex.

Adaptive air suspension and four-wheel-drive combine to make the Panamera lighter on its feet than this car has any right to be. Porsche’s dogged commitment to is sporting roots mean the company has sacrificed ride quality in the name of laptimes. That’s borderline ridiculous with a luxury car, but it’s just the way Porsche rolls.

The Mercedes comes with Airmatic suspension, torque vectoring and some other tricks that we’ll get to shortly. But it has different goals in life. The car weighs in at 5,115lb, but that’s not the issue. It’s tuned for a magic carpet ride and it’s rear-wheel-drive. So on a track it simply wouldn’t see which direction the Panamera had gone.

Mercedes S550e Plug-in Hybrid vs Porsche Panamera E-Hybrid: Electric-Only Mode

Now things start to get a little interesting. The Mercedes can run in electric-only mode up to 87mph and comes with an all-electric range of 20 miles.

That’s just the start of it, though, as the electric motor is packaged in the gearbox and provides regenerative braking system that is linked to a radar system and adjusts to reap as much additional power as possible. It even gives you a haptic buzz on the throttle pedal that tells you when to lift. That’s cute, and it means, if you’re driving in stop start traffic, a tank of gas could last you months.

The Porsche has 31 miles of electric-only range and can hit 87mph before the engine kicks in as well, which is a weird coincidence, but the system just isn’t as sophisticated. Still, somehow, the Porsche manages to beat the Mercedes.

Mercedes S550e Plug-In Hybrid vs Porsche Panamera E-Hybrid: Economy

Mercedes uses a relatively conservative 54MPGe rating for the S550e Plug-In Hybrid, while Porsche has gone all out with an ambitious 94MPGe claim backed up by the much more generous European authorities.

The truth is that the numbers are borderline irrelevant in the real world and the fuel you use will depend on the type of driving you do. Independent testers found the Mercedes returned around 21mpg in the city

We have to assume, considering how similar the cars are in terms of output, that the economy figures will be largely the same. If anything, Porsche’s four-wheel-drive system could count against it and give Mercedes an almost imperceptible edge.

Mercedes S550e  Plug-In Hybrid vs Porsche Panamera E-Hybrid: Interior

After taking a pasting in the performance stakes, Mercedes has been looking forward to this one. That’s because this might be a hybrid, but it is, primarily, an S-Class. Ever since the Three-Pointed Star adopted the S-Class  name in 1972, it has been synonymous with cutting edge technology and absolute, near unparalleled luxury.

The leather is handstitched, the wood is handcrafted and the buttons are neatly contained in the center console. It’s a clean design and everything is at your fingertips with the touchpad controller, while the two high-resolution screens provide all the vital driving information, navigation and a separate entertainment system for the passenger.

The seats have six in-built massage programs, every seat feels like First Class, the panoramic roof makes  the whole car feel light and airy and optional infotainment screens in the back turn it into a mobile cinema. The whole car is a WiFi hotspot and we could honestly go on for hours about the user experience.

Porsche has closed the gap with the latest car, a lot, but the sporting DNA runs through the car and the marque just hasn’t quite got the hang of full-on luxury. It will, but it’s not there yet. It has a traditional, analog rev counter in the center of a digital instrument binnacle to complement the 12” touchscreen.

Porsche offers optional sports seats, for those that want to pretend they’re in a 911, and the rear seats are individual chairs for added support. In fact, both cars are strictly four seaters, which could be an issue with bigger families.

There’s a touchscreen in the rear, too, to access the four-zone climate control and infotainment that includes optional screens for the passengers. It’s even got a panoramic roof, too, and the second gen Panamera is a quantum leap forward over the fugly interior of the original. But it can’t match the Mercedes and the Porsche loses this one convincingly.

Mercedes S550e Plug-In Hybrid vs Porsche Panamera E-Hybrid: Practicality

The Mercedes loses some serious bootspace thanks to the hybrid system and you actually get 13.9 cubic feet, compared to 18.7 cubic feet in the standard car. That is significant, especially when it’s going against the shooting brake style design of the Panamera. In fact, it’s decisive. The Porsche provides 15.7 cubic feet, so it can take more luggage.

Mercedes has an ace in the hole thanks to its work on wireless charging, though, so the optional wireless charging pad that you can order from 2018 with the facelift model could swing your vote in the sedan’s favor. But you can’t have that now, so it might be unfair to mention it.

As for charging time, Mercedes has developed an ‘inefficient charge’ mode that means you can use the petrol engine to charge the battery and Porsche has an equivalent with its E-Charge. It kind of defeats the point of having the battery in the first place, but it’s clever tech.

The Porsche takes about 12 hours to full charge on a 120V supply with the standard 3.6kW onboard charger, which really doesn’t sound enticing in the modern age for a hybrid car. With the optional 7.2kW charger and a 240V supply, that figure drops to a much more acceptable three hours.

The Mercedes reportedly charges fully in four to five hours from a 120V supply, or in as little as two hours from a 240V outlet.

Mercedes S550e Plug-In Hybrid vs Porsche Panamera E-Hybrid: Trick Tech

The S-Class has always been Mercedes’ skunkworks for clever technology that eventually filters down to the rest of the range. Now there’s an issue with this and that is the new E-Class has temporarily usurped the S-Class with self-driving tech, but the German marque will put that right next year with the facelift model.

The new S-Class was launched in 2014, but it still comes with driver assist, a limited self-driving capability. So it can drive and handle the basic steering up to 124mph. It has a night vision camera with animal detection, which is important in some parts of the world. It also features the Magic Body Control suspension that reads the road surface ahead and adjusts the damping to compensate for the surface.

The hot stone massage function is a gimmick, but it all adds to the user experience and it could become a real selling point when the car really does drive itself.

Porshe has its own Adaptive Cruise Control, which uses a radar system to regulate the distance to the car in front and the car will also warn you if there’s something in your blind spot. It’s a long way off Mercedes’ self-driving tech, but Porsche believes that its owners want to drive. It might have to look at that philosophy in the very near future.

A lot of the tech on the Panamera is based around speed, like the eight-speed PDK gearbox and the torque distribution of the four-wheel-drive system. It’s clever stuff, but it also highlights Porsche’s traditional outlook. Other manufacturers are riding a wave of technology and even the smartest traction control system is suddenly a little old hat.

Mercedes is comfortably ahead here and the likes of Tesla and Faraday Future are just about as far ahead again. Porsche might keep is market share with this approach, but we kind of doubt it.

Wrap up

Both the S-Class and the Panamera are exceptional cars and they’re sporting, luxurious class leaders in their own special way. We have our reservations about these hybrids, partially because they’re a compromise and a halfway house.

There are fully electric alternatives that we have to say make a more enticing prospect right now, including the Tesla Model S. But for owners that want a traditional prestige badge and aren’t ready to embrace change to quite that extent, then they’re both very solid cars.

So which one wins? It really depends on you…

The Mercedes is the better luxury car, it just is. It is loaded with clever tech, it comes with that iconic badge and the S-Class really is a high-tech alternative to the likes of the Bentley Continental or even the Rolls-Royce Wraith. Judged on those terms then it’s an absolute bargain and the fact that it’s a hybrid that comes with a $4800 incentive means it’s really a car that a CEO should consider.

The Panamera is the luxury car for someone that still thinks they want a sportscar, even though they really don’t. It will offer more smiles per mile than the Mercedes, it will hug the apex and it sounds good when you’re on maximum attack. The only concern is that those times will be few and far between. If they’re not, then you should buy a 911 instead or certainly one of the more flamboyant, petrol-only Panameras.

So the logical choice would be the Mercedes. It’s more cohesive, it’s more comfortable in its own skin and it actually fulfils the brief a little better than the Porsche. You wouldn’t be upset with either car, but if you want a luxury hybrid then the Mercedes makes a more compelling case.