There's one thing that exasperates Mercedes-Benz's director of development for the luxury S-Class sedan, Dr Henmann-Joseph Storp, and it's to do with rear headrests.
"The cushions, that's all anyone ever talks about," said Storp.
Despite the effort he and his team put into making the latest S-Class the most comfortable, safe and technologically advanced sedan in the world, all anyone comments on is the soft, pillow-like cushions attached to the rear headrests.
In fairness, though, they are pretty special, and with the launch of the new Mercedes-Maybach they're now in an even more luxurious car.
Yes, Maybach is back. Mercedes discontinued this super-luxury brand in 2012 after years of poor sales. But the badge is now being applied to the longest and most indulgent version of the S-Class yet, albeit under the name Mercedes-Maybach rather than as a standalone brand.
For now, in Britain at least, there's a single model based on the S600, which uses the same 6-litre biturbo V12 engine (a V8-engined S500 variant and four-wheel drive will be offered in other markets while Mercedes-Benz NZ says it'll bring one in on customer-order basis only).
However, Storp says there will also be Maybach versions of other Mercedes cars: the GLS 4x4 is certain to be offered in Maybach guise, while stretched E-Class models would be a natural fit in China, Maybach's anticipated largest market.
Mercedes-Maybach will also introduce a six-seater Pullman S-Class, which will add significantly to the 207mm stretch the "standard" Maybach has over the far from poky long-wheelbase S-Class.
Until this arrives, though, the world's super wealthy will just have to make do with the car you see here. Storp says it took more than two years to develop and claims it's the quietest sedan car in the world.
To create the new Maybach, Mercedes strengthened and lengthened the S-Class' body, with all the extra space going to the passengers in the back.
The rear doors were reshaped, too, to give greater privacy, and their seals improved to make sure passing wind creates little more than a whisper. In addition, the glorious V12 engine sits behind acoustic deadening borrowed from the S-Class diesel range to better silence its mighty output.
Acoustic deadening and foam-filled tyres help make riding in the Mercedes-Maybach S a quiet and relaxing experience.
All this work means the Mercedes-Maybach S600 is indeed a remarkably quiet car. Mercedes even went to the trouble of sourcing foam-filled tyres to help damp out road noise, a solution borrowed from Audi, which uses the technology to quell tyre roar in its sporting S models.
There's acoustic deadening behind the rear seats, too; Storp says he and his team investigated active noise cancellation but the results gained via conventional passive technology meant it wasn't required. He doesn't rule it out for future models, but this time the only electronic acoustic addition is discreet amplification of the driver's voice so that he or she can be better heard in the rear.
This is where most Maybach owners will sit, of course, but for the benefit of any chauffeurs out there, we had a go in the front as well.
You can feel the Mercedes-Maybach's greater mass in corners, but that V12 engine makes light work of it on the straights. What's more, the seven-speed automatic gearbox is as slick as ever, even if the presence of a "Sport" button seems incongruous in this application.
As you might expect of Mercedes' flagship model, just about every driver aid is fitted as standard, be it for safety, comfort or convenience. That includes Magic Body Control, a road-reading adaptive suspension system that can smooth out speed bumps at speeds up to 40km/h.
There's also night vision, ionised scented air, a panoramic glass roof with adjustable translucence, a head-up display for the driver and a sensational 24-speaker Burmester 3D surround-sound stereo system.
Choose the First Class seat option and the standard rear bench is replaced with a pair of reclining, cooling or heating, massaging seats that'll redefine your definition of comfort.
True, these are available on all versions of the S-Class, which might make the return of Maybach seem pointless. Indeed, the cynical could write it off as just a badging exercise. However, in reality Mercedes has succeeded in its aim of creating the quietest, most luxurious and most comfortable S-Class yet.
In doing so, and adding that Maybach distinction, it better allows this car to compete against the offerings from Rolls-Royce and Bentley, even if it still doesn't have quite their cachet.
But in every other way the Mercedes-Maybach S600 is a definitive luxury experience. And yes, the soft, pillow-like cushions attached to its rear headrests play their part.
-Telegraph Group Ltd