Service-oriented architecture was designed to sup- port the development of massively distributed applications that communicate over the Internet. Different services may be com- posed using service compositions schemes, mainly orchestrations and choreographies. However, to evaluate how the characteristics of the environment affect the QoS requirements of the composi- tions is a difficult task. To be able to do so, we developed a SOA simulator, estimated and compared the performance for two real- world scenarios developed using orchestrated and choreographed implementations. Proper choosing of the service composition may incur in significant performance enhancement. In our experiments, the average response time using choreographies was up to 50% lower than its orchestrated counterpart. Besides, for the same available bandwidth, choreographies presented response time lower than orchestrations.