This may be of some help for you. First I own a 1995 LS400, bought new, that my wife drives. I also own a 2002 Mercedes ML320, also bought new, that I drive. There is no comparison in the service departments, with the Lexus head and shoulders above the Mercedes. With the ML, I had a factory 50,000 mile warranty and even though something was obviousley broken, and obviously covered by the warranty, they acted like they were doing me a big favor to fix it. Now that I am out of warranty, I go to a local shop owned by a former Mercedes SA and he appreciates my business and is usaually about half the dealer cost. I recognize that the ML is not the car you are looking at, and that it is a truck, and drives like one. The LS400 Lexus is our second with the first being a 1995 ES 300. The ES300 had a sportier suspension and the LS 400 much softer. Both were excellent cars. Right now, I have no plans to buy another Mercedes, but have no qualms with another Lexus.
Bob