Consumer Reports, the influential product review publication, says AT&T Inc. is again the worst-rated cellular service provider in the U.S., a blow to the carrier’s effort to rehabilitate its network and reputation.

The conclusion, based on a survey of 58,000 readers, shows customers continue to hold AT&T’s service in low regard even after the carrier boosted its wireless spending by $2 billion this year in an effort to correct what it has acknowledged were weaknesses in its network.

The results bode poorly for AT&T as it faces possible competition for Apple Inc.’s iPhone, a device it carries exclusively now and relies on for much of its subscriber growth. In fact, Consumer Reports found “iPhone owners were, by far, the least satisfied with their carrier.”

“We take this seriously, and we continually look for new ways to improve the customer experience,” AT&T said in an emailed statement. The carrier pointed to its success attracting customers and claimed its dropped-call rate is only slightly worse than the best in the industry.

Apple is making a version of the iPhone that Verizon Wireless, the country’s largest wireless carrier, will sell early next year, people familiar with the matter have said.

Verizon came in second in Consumer Reports’ ratings of cellphone carriers, behind U.S. Cellular Corp., which has just 6.1 million customers, compared with Verizon’s 93.2 million.

One company to come out well from the survey was the third-largest U.S. wireless carrier, Sprint Nextel Corp. Its overall satisfaction rating pulled nearly even with Verizon’s, an indication the company’s effort to improve service and build up its device lineup is getting through to consumers.

AT&T, the second largest U.S. wireless carrier, has been dogged by questions about its network quality for about as long as it’s carried the iPhone, released by Apple in 2007.

Users have complained loudly about dropped calls in particular, a result of the network stress brought on by iPhone users’ heavy data traffic.

AT&T has acknowledged that it didn’t foresee the spike in demand and that its call quality fell short, particularly in New York City and San Francisco.

This year, AT&T boosted its capital spending to shore up the network. It claimed to have largely finished the work in New York this summer, but said work in San Francisco was being held up by equipment shortages and zoning issues.

The efforts didn’t register with the readers Consumer Reports surveyed. AT&T got the lowest ranking on eight of nine measures of customer support, service and value.

The publication said AT&T was the only carrier to see a substantial drop in its overall satisfaction score from a year ago, falling to 60 from 66.

(Source: Wall Street Journal)