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Groovyws is super fast but super slow
It's super fast when you consider that from a wsdl file, it's compiling 20+ classes for you.
It's slow when you have to do this for every request. I opened a JIRA issue for it. http://jira.codehaus.org/browse/GMOD-85
For now, I am going the old-fashioned route and generating a java client and using that in my Grails application