The study (now in its 12th year) measures the satisfaction of customers who have visited a dealer service department for maintenance or repair work in the fourth or fifth year of ownership. Scores are based on six factors: service initiation (how easy it is to get an appointment), service advisor performance, service quality, user-friendly service, service delivery and in-service experience.

Overall satisfaction with dealer service averaged 866 on a 1,000-point scale, an increase of three points since 2007. Among the 34 dealer brands included in the study since 2007, nearly seven in 10 have improved since the previous year.

"We've seen a narrowing of the difference between the two," says Tom Gauer, senior director of automotive retail research at J.D. Power. "Dealers are more competitive than they were five or six years ago. In 2004, non-dealer service facilities scored around 20 points higher than dealerships in this study. In the past two years, there has only been a four- or five-point difference."

Acura, Cadillac, Jaguar, Lexus and Saturn perform particularly well among dealer service customers, while Goodyear Tire and Valvoline Instant Oil Change lead the non-dealer segment.

With new car sales plummeting, dealerships have increasingly focused on their service operations in an effort to recapture lost revenues and boost customer loyalty. Dealerships are now experimenting with different service models, like quick oil change lanes, to capture more of this routine maintenance work that might otherwise go to non-dealer facilities.

"There are statistics that show if you visited a dealership for service in the last six months, you are more likely to purchase a new vehicle at that dealership," says Jim Phillips, dealership management consultant with the National Automobile Dealers Association (NADA). "Dealers are now getting into the competitive maintenance game. Customers want dealers to be competitively priced for repairs like oil changes and alignments. In the past, they were trying to charge $80 an hour for an oil change, because that was their labor rate. That just doesn't work."

One reason dealerships have increased their satisfaction scores is a shift in the proportions of repair and maintenance service visits. In 2008, 58 percent of customers visited the dealer for maintenance work, while 42 percent visited for repairs. That's a slight shift from 2007, when the ratio was 54 percent for maintenance and 46 percent for repair work. According to Gauer, satisfaction is generally higher for maintenance work (878, on average) than it is when customers visit the dealer for repair work (849, on average).

Customer service is a key driver for both satisfaction and customer loyalty. Customers who report experiencing a personal connection to their service advisor are five times more likely to report their service experience exceeded their expectations. In addition, 75 percent of customers who said their expectations were exceeded indicated they "definitely will" return to their service dealer for future customer-paid work, compared with only 42 percent of customers who said their expectations were merely met.

Among non-dealer facilities, independent garages generally provided higher levels of satisfaction than other facilities, including gas station service, specialty service and retail service facilities. According to Gauer, this can be attributed, in part, to the personal connections customers report having with the service staff, as well as the quality of service provided.

"One of the top reasons for using a non-dealer facility was because the customer had a previous good experience there," Gauer says. "Once they have a good experience at a non-dealer facility, it's very hard for the dealership to recapture those customers."