Sales figures and if the trend is up or down over time are important. Usually strong sales mean customer satisfaction. Sometimes it means that a business has a unique product with little or no competition but typically sales and customer satisfaction are correlated. Customer loyalty or repeat business is another important dimension of customer satisfaction. Brand recognition is another.
Outstanding organizations have products that are recognized and respected.
More sophisticated efforts lead to an understanding of customer success with one's own efforts and that of competitors'. A company will purchase a competitor's product or use their service to determine how it compares or benchmarks against their own. Products will be examined in careful detail to determine the durability, cost, and desirability. Businesses will comparison shop to examine a competitor's range of options, price, availability, quality, location, delivery alternatives, service capability, convenience, and product guarantee. Many businesses will also use mystery or phantom shoppers to gauge how well their employees' respond to their own customers.