While the industry average was up seven points on last year, reflecting an improvement across all vehicle segments, only four mass-market brands were above the mark: Volkswagen (812), Ram (792), Ford (791) and Chrysler (789).
Although three out of five buyers in the study remained with the same size car they had before, those changing sizes were more than twice as likely to downsize rather than move into a larger segment.
More than a quarter (27 per cent) of respondents either bought or leased smaller cars, compared to 13 per cent of buyers who up-sized.
JD Power and Associates' vice-president of global automotive, David Sargent, says buyers were increasingly finding that "today's compact models are not the 'econoboxes' that they may have once feared".
"What we're finding is that appeal has increased rapidly over the last few years. Although consumers are downsizing, they're not actually downgrading.
"They are just as satisfied, if not more so, than they were with the previous larger vehicle."
Sargent pointed to the more substantial nature of new-generation compact vehicles, their improved performance, increased features and appointments that were once found only on larger models.
"Vehicle owners who downsize are often finding that they are actually upgrading when they buy a new vehicle," he says.
This is reflected in the increasing average APEAL score for smaller cars in recent years, climbing to 765 points in the compact/sub-compact segment this year - the level that mid-size vehicles enjoyed only four years ago.
Similarly, the 2012 average APEAL score in JD Power's mid-size premium segment is 844, which is the same as the average for large premium vehicles in 2008.
In specific segments, the Chevrolet Volt (to be launched in New Zealand later this year under the Holden badge) was this year the highest-ranked compact car, with the VW Golf and Honda CR-Z next best, while the Mini Coupe/Roadster led the compact sporty car category ahead of VW's Golf GTI and the Mini Cooper. The top sub-compact car was the Chevrolet Sonic, with the Fiat 500 and Ford Fiesta next, while Mercedes took out the compact premium sporty car section with the SLK-Class.
Other category winners included the BMW 3 Series (entry premium car), Porsche 911 (premium sporty car), Kia Optima and VW Passat (medium car joint winners), Dodge Challenger (mid-size sporty car), Audi A6 (mid-size premium car), Dodge Charger (large car) and Audi A8 (large premium car).
Among the highest-ranking crossover/SUVs were the Mini Countryman (compact), Range Rover Evoque (entry premium), Ford Flex (mid-size), Porsche Cayenne (mid-size premium), Ford Expedition (large) and Infiniti QX56 (large premium), while Kia's Soul took top honours in the compAct MPV segment.
Rounding out the segment winners, Chevrolet bagged its third individual category award with Avalanche named the top-performing large pick-up - ahead of Ford's F-Series models - while Nissan claimed top mid-size pick-up with the Frontier and top minivan with the Quest.
Although Chevrolet won three individual categories, the General Motors brand was below average as a whole, on 777 points. Other below-average brands included Kia (786), Buick and Hyundai (784), Toyota and GMC (780), Honda (771), Mazda (770), Nissan (769), Fiat (768), Jeep and Scion (764), Subaru (761), Mitsubishi and Smart (752) and Suzuki (745).
Luxury brands dominated at the top of the table. Behind Porsche and Jaguar were, in order, BMW (859), Audi (848), Mercedes-Benz (844), Land Rover and Lexus (833), Cadillac and Infiniti (823), Acura (816), and Lincoln and Mini (815).
-Go Auto
