In one of the first independent surveys of the users of Health Maintenance Organizations, CareData Reports of New York has compiled a list of what it says are the best HMOs in the United States. The health plans rated most satisfactory by 10,272 members of 33 different HMOs were: Kaiser Permanente in Connecticut; Aetna Health Plan in greater Cleveland; Cigna Healthplans in Houston; Oxford Health Plans in New Jersey; and Kaiser Permanente in Southern California. Even the best could work on their bedside manner, however. CareData reports that customers who were pleased with their HMOs tended to think the medical care was better than the customer service. At the same time, healthier patients may find it easier to have confidence in HMOS. The survey found that younger patients tended to be happier than older ones with complex life-threatening problems like cancer.