Choosing between SOAP and REST web services
When designing a web service, spend time considering both the end user and the service itself. For example, how many requests do you expect the service to handle on an average day? A RESTful web service–that is, a service that conforms to the REST architectural style–tends to use less bandwidth and memory; however, a service that uses the SOAP protocol may be better suited for an enterprise application.
For more information on the benefits of SOAP and REST, including why you may want to choose one architectural style over the other, open the PDF.