ACE Rent A Car topped the J.D. Power and Associates 2011 rental car survey,

based on responses from 12,500 business and leisure travelers. Overall satisfaction with rental car companies this year improved slightly to 758 on a 1,000-point scale from last year's 750-point average. Following ACE, which earned a 793-point rating, Enterprise, National and Hertz posted above average scores. Alamo, Budget, Dollar, Avis and Advantage were rated below average. Thrifty and Fox Rent A Car fell to the bottom of the rankings, with an average score of 726 and 716, respectively. Fielded between January and September, the J.D. Power survey asked travelers who recently had rented a car from an airport to rate rental car providers in six weighted categories: cost, pick-up process, return process, vehicles, shuttle services and reservations.