The core value of automation for Manufacturing Execution Systems (MES), or Manufacturing Operations Management (MOM), is to enable on-time delivery of a quality product at the lowest cost. Very often, the decision to shift to MES or MOM automation is accompanied by considerable management debate over whether to invest upfront capital into a thirdparty software solution, or have the organization’s highly skilled employees put time and effort into the development of an internal software. This paper reviews the advantages and disadvantages of making or purchasing a MES or MOM automation solution.