Overall customer satisfaction with residential high-speed Internet service providers “decreased slightly from 2009,” because of declines in satisfaction with cost of service and offerings and promotions.

That’s theconclusion of the newly-released J.D. Power and Associates 2010 Internet Service Provider Residential Customer Satisfaction Study. The study measures customer satisfaction with high-speed Internet service based on five factors: performance and reliability; cost of service; billing; offerings and promotions; and customer service.

The study also finds that customer satisfaction with cost of service averages 584 in 2010—a 12-point decrease from 596 in 2009. Contributing to this decline are decreases in satisfaction with fairness of prices paid and ease of understanding pricing options.

High-speed Internet service providers are examined in four regions:

East Region: Optimum (News - Alert) Online ranks highest with a score of 659 and performs particularly well in two of five factors: offerings and promotions and customer service. Verizon follows in the regional rankings with a score of 658, while EarthLink ranks third with a score of 643.

South Region: With a score of 675, Verizon (News - Alert) service ranks highest in the South region and performs well in the performance and reliability and offerings and promotions factors. EarthLink follows in the rankings with a score of 672, while Bright House Networks' RoadRunner service ranks third with a score of 661.

North Central Region: Performing particularly well in all five factors driving satisfaction, WOW! ranks highest in the region with a score of 722. Cincinnati Bell follows with 674, while Cox (News - Alert) Communications ranks third with 671.

West Region: Cox Communications ranks highest in the West region with a score of 659 and performs particularly well in performance and reliability, cost of service, billing, and offerings and promotions. Following Cox in the regional rankings are Cable One (646) and EarthLink (642).