So here we go.
Audi has the wealthiest buyers on average in terms of income. They make the finest interiors in the entire auto industry and have done so for quite some time. Their awards for interior supremacy only help to further soldiify and justify this claim
BMW has their sporty reputation which is second to none (except for maybe Porsche)
Lexus has their reliability which can be touched by no other luxury manufacturer
Mercedes-Benz has their luxury gt cruisers and heritage.
THERE IS SOMETHING FOR EVERYONE. People who want interiors and to have the wealthiest customer base out of any car company (on average) can get an Audi, those who want reliability get a Lexus. Those who want athletic performance buy a BMW and those who want a luxury gt cruiser with heritage get a Mercedes - Benz.
No luxury brand is inherintely better than any other. Each company has its own strengths as well as weaknesses.
Time to end these flame wars