Simple XML-RPC interfaces can be OK, and they often have real documentation available, since they are not assumed to be magic, and that documentation will be needed. (we use several of these from a few vendors at work, they were not problematic to set up)
I've experienced a lot of pain trying to get working clients generated and configured from some magic WSDL (SOAP interface definition file), though. For a supposedly self describing standard, each time I have had to write a client, it was very much an "interesting" adventure.
My gut tells me there are many "Web Services" consultants who do not like REST because it simplifies things to the point where they are out of a job :-)
I've experienced a lot of pain trying to get working clients generated and configured from some magic WSDL (SOAP interface definition file), though. For a supposedly self describing standard, each time I have had to write a client, it was very much an "interesting" adventure.
My gut tells me there are many "Web Services" consultants who do not like REST because it simplifies things to the point where they are out of a job :-)