My Lexus sales esperience is very good at one particular Lexus dealership that I work with exclusively. When I want to test drive a car, they just give me the keys, no dead weight salesperson in the car, no prob.
The Mercedes dealership a couple doors down the street gives similar level of customer service, very good. I think they learned from the Lexus dealership.
As I mentioned in another post for Lexus and added personality, F-sport helps a lot. Just like M stuff helps BMW and AMG stuffs help Mercedes cars become more entertaining. The customer can configure some tasty premium cars from all 3 of these major brands, and still not go to expensive extremes like IS-F, E63, M5, etc.