Over at InfoQ, Stefan Tilkov has a nice article based on interviews he conducted with lead developers of various open source stacks - Axis2, CXF, Spring Web Services, JBossWS, and obviously GlassFish's Metro. Koshuke "I have many hats" Kawaguchi Clearly explain how Metro had standard support (both WS-\* and JAX-WS) and interoperability as design goals. Others recognize JAXB's full support for XML Schema as a very strong point.
One question asked relates to support for the REST principles. You could consider the
Dispatch APIs to be good enough to work with the HTTP protocol without using SOAP, but as Kohsuke points out, the RESTful work at Sun is going on in the Jersey project (now in version 0.3) which is closely tracking the evolution of JSR 311 and involving much more than just Sun.
The article has both a summary and the un-edited answers from all participants. Some interesting tidbits here and there.