From my experience nothing interoperates well, even in the basic SOAP stack. rpc/encoded used to work OK, within its limitations but now that’s deprecated it’s not a realistic option for new services. So you’re stuck with document/literal where practice isn’t great.
Ouch. Even if you like the (presumed) architecture of Web services, this would seem reason enough to give pause and to motivate consideration of a Web based solution, no?
Update; based on some offline feedback, I should clarify that the problem Nelson talks about with the doc/lit encoding isn’t specific to Web services and could also be encountered in a Web based solution. But my intent here is just to throw cold water on the general concept of “SOAP = interoperability”, and to point out that the largest distributed application ever created by mankind – the Web – got that way because it truly embraced interop, and wasn’t just paying it lip service.