At this stage I think BMW has and will have the leading position in terms of design, their designs are a mix of their history such as the circular headlamps (emphasised by angel eyes) and the Hofmeister kink and its distinctive side swage line, which are things dated way back in history, while adding mixes of new elements such as flame surfacing, ultra short front overhang and a relatively wide wheel arch. The CS concept and M1 Hommage shows how much potential they've got in their pockets.

Mercedes is the most harmonious, i mean, it always look good and classic, but imo that is from the Eclass onwards, the Cclass and things below it I reckon are a bit too small to excel the 'classic' and sleek harmony that is in their design element, so something is missing for those smaller models... well, MB never made small cars until the 190E. I'd say the details are not as detailed as BMW's, but often turns out looking better and easier to accept overall.

Audi, recent designs, they look good, but a bit boring, 1 sausage in different lenghts lately. And I guess their history isn't as strong as the other two, so there isn't much to follow, for example their DRL is quite random, while the 4-square tail light is more meaningful. R8 is great though.