One quick point - transmission protocol and orchestration;
I use SOAP over TCP for speed, reliability and security reasons, including orchestrated machine to machine services (ESB) and to external services. Change the service definition, the orchestration raises an error from the WSDL change and its immediately obvious and can be rebuilt/deployed.
Not sure you can do the same with REST - I await being corrected or course!
With REST, change the service definition - nothing knows about it until it returns 400 (or whatever).