BMW F generation 6 series interior design is probably my favorite in terms of overall quality, feel of materials, layout/design, and practicality
The waterfall effect is simply stunning and when trimmed properly in Carbon Fiber, leather, and Alcantara, its heaven!
Nothing compares to it from Audi, Mercedes AMG GT 4 series and S class are also beautiful and I'd consider them better designed but nothing else from Benz