I always create POM from scratch, but if you ask me, I would choose the POM created by the artifact.
The POM created by WebAppCreator launches DevMode in target/www, which is strange, and includes a configurator maven-clean-pluginthat is simply not needed (you should never run DevMode using the src/main/webappdirectory as your war, so there is no need to clear it)
The POM generated by the artifact, on the other hand, uses targets i18nand generateAsyncwhich IMOs are not needed (they can be useful as tools for a single shot, but not run on each assembly, in particular i18n).
If you ask me, none of them will be a good starting point, but the artifact is less bad than WebAppCreator.
EDIT: : https://github.com/tbroyer/gwt-maven-archetypes , IMO gwt-maven-plugin WebAppCreator.