O'Reilly Auto Parts is a preferred parts store for many customers in the Denver area. The employees are generally helpful and able to meet the customers' needs, going above and beyond in some cases. The Denver store is praised for its fast and friendly service, fair pricing, and customer-oriented approach. The staff, including a manager or assistant manager named Dan, are commended for their willingness to assist customers and provide exceptional service, such as replacing a battery and offering a ride back to the customer's original location. Overall, O'Reilly Auto Parts is a reliable and customer-focused business.