I've had positive experiences with wsdls, they offer a lot of advantages over REST/JSON, together with some up front onboarding costs.
It really depends on the service, does it make it easy to obtain the wsdl and more importantly does it honor the type conventions. There is no getting around the fact that services need to maintain consistent behavior and document that behavior, the wsdl is just a transport layer for that organizational commitment. If you have the commitment, then you have a good experience, if you don't, you don't, and whether you are using JSON or SOAP doesn't matter.
It really depends on the service, does it make it easy to obtain the wsdl and more importantly does it honor the type conventions. There is no getting around the fact that services need to maintain consistent behavior and document that behavior, the wsdl is just a transport layer for that organizational commitment. If you have the commitment, then you have a good experience, if you don't, you don't, and whether you are using JSON or SOAP doesn't matter.