Porsche is top of the influential US J.D. Power and Associates 2010 Initial Quality Study - but the results make disappointing reading for most European brands.
The J.D. Power study measures owner complaints after approximately 90 days of ownership.
Aside from Porsche's success and Mercedes's top-five ranking, European manufacturers suffer a poor showing. Most notably Audi, BMW and Jaguar are all lagging below industry average and Land Rover was the lowest-rated of all brands included.
Toyota took a severe tumble, falling from sixth a year ago to 21st as a result of its quality problems and subsequent recalls.
Lexus, however, remained in the top five, while the Lexus LS notched up the industry-best score for an individual car.
Ford also became the first Detroit car maker to enter the top five.