O'Reilly Auto Parts in Derry offers a mix of positive and negative experiences. Customers appreciate the friendly and welcoming staff, highlighting excellent customer service from team members like Chris and Greg. They find the store convenient for in-stock parts, such as air and cabin filters, with quick service. However, some customers have concerns about staff experience, noting that some employees, including managers, may lack product knowledge and show little interest in helping. There are frustrations with special order parts, which now require shipping and additional costs, rather than being readily available or sourced from other locations. Mistakes in orders, such as receiving the wrong part, have also occurred, but customers remain loyal to the store. Overall, while the staff's friendliness and in-stock availability are praised, issues with staff expertise and order accuracy are noted.