Honda has won this year's Reliability Award, based on a Which? readers' survey of 100,000 cars, beating the Best Manufacturer Award-winner Toyota.
The Green Award went to hybrid champion Toyota, ahead of runner-up BMW, which won the Road Testers' Award.
Some models by US marques Chevrolet, Chrysler and Dodge were criticised due to safety concerns.
Volvo's safety image was let down by concerns about seatbelts, which enabled Ford Galaxy and Toyota Auris to jointly grab the Safety Award.
Lexus won the Ownership Award ahead of Honda, though the Honda Jazz was this year's most reliable individual model.
Safety-conscious car buyers should steer well clear of the Chrysler Voyager, a people carrier, the Dodge Caliber, a medium-sized car, and the Chevrolet Matiz, a rebadged small Daewoo, Which? said.
The only serious non-Japanese contender for the Reliability Award was Korea's Hyundai, which came joint third - alongside five Japanese marques: Daihatsu, Lexus, Mazda, Subaru and Suzuki, with Mitsubishi following closely behind.
Ford and Nissan also scored highly in the reliability stakes, though when considered at a group level they were both pulled down by their sister-marques.
Renault, Nissan's partner, and Land Rover, which is owned by Ford Motor, were at the bottom of the reliability league table.