Hi,
The advantages i could notice:
    - possibility to 'mark' keys as dirty (need rework)
    - possibility to add bookmarks if i remember well
    - easy to see what is not yet translated
    
But i'm pretty relectant to use gettext for JBoss Portal localization.
    
exactly ;)

In eclipse it would be against everything else so at runtime it should 
be properties.
  
Another advantage of using gettext is, there is an existing localization team in Red Hat could be leveraged for the all JBoss modules when the I18N infrastructure on JBoss could be integrated with current workflow (e.g. tools, work file formats, etc.) of them. They have done the translation for JBoss Installer and they are very familiar on working with .po files that are used by gettext.

Caius.