I can tell you as a former O'reilly employee that they generally sell good stuff. Their brakes are pretty decent , made by Federal Mogul and batteries are made by Johnson Controls . Engine Management parts are BWD with a housebrand Masterpro , not sure of the manufacturer of the Masterpro parts. Suspension components are Moog as well as the Masterpro housebrand , while belts and hoses are Gates products. In general compared to the rest they are about the same, their brake parts are a good deal while the Gates parts are very high quality. Their selection of oil products does disappoint with alot of shelf space devoted to their Omni lubricants produced O'reilly house brand oils. In general though it is a good place to shop, prices are usually lower than the competition with warranties on their parts that are much better . It really depends on the employee's though , my O'reilly was employed by people who love cars and cared about customers , I hope yours is too.