The fact that SOA enables integration of widely different systems introduces a big problem for businesses: Governance. Because the platforms, frameworks, and applications used are abstracted, there is a tendency for programming standards and best practices to get brushed aside. The advantages from integration quickly turn to risks if governance is enforced. This is because problems from any application can cascade into other applications that leverage it.
Governance is expensive and time-consuming. Ensuring applications across a business are developed to be reusable and follow new standards cuts into both development cost and time. However, the benefits of SOA in the long run outweigh these costs, and governance mitigates the risks of faulty services.