Look and feel is most important to mobile phone buyers, but the ever-increasing complexity of the devices has made ease of operation a close second, researcher J.D. Power and Associates said Thursday.

In a study measuring customer satisfaction, J.D. Power found that the physical design of the wireless phone was most important, followed in order by ease of operation, features, durability and battery life.

The results, based on responses of 17,701 U.S. households with people who owned mobile phones for less than two years, showed a major shift from 2003. Since then, the importance of design and operation has increased dramatically.

Consumers are looking for phones that are easier to use because of the growing complexity, as manufacturers add video and still cameras, music players, and software to support various data and multimedia services.

"There are so many more features and services now that (ease of operation) is becoming much more important," Kirk Parsons, senior director of J.D. Power's wireless services, said. "There'll be even more features five years from now."

Consumer attraction to design is evident in how quickly sales of clamshell-design phones have surpassed the candy bar-type handset. In 2002, 70 percent of mobile-phone users had the latter, and 7 percent the former. This year, the numbers are 45 percent and 52 percent, respectively.

"People are voting with their dollars," Parsons said.

Characteristics of the clamshell-design that consumers find attractive are the smaller size, the sleeker look and lighter weight. As a result, customer satisfaction is significantly higher with these devices than with the candy bar-shaped phone.

Among the handset manufacturers, LG and Sanyo ranked highest in a tie in overall customer satisfaction. LG performed particularly well in physical design and battery life, J.D. Power said. Sanyo received the highest ratings for operation, durability and features.

Other vendors that scored above the industry average were Samsung and UTStarcom.

In other study findings, the average handset purchase price decreased this year to $89 from $99 last year, and the average replacement cycle for the typical handset was 18 months.

The feature on the phone used the most was the speakerphone, followed in order by short-message services, gaming and cameras.

Half of all current wireless subscribers compared handset brands before settling on one. Those who did their homework were more likely to be satisfied overall with the product they bought.

In the future, Parson expects battery life to rank much higher with consumers, who today have to trade features with more trips to the re-charger.

"That's the main complaint that people have today," Parsons said.