Hi Daniel,
I think CMigrator is a great tool but it currently lacks the following :
- ability to directly import from a WP database (not having the tables in the same database as the joomla database),
- ability to delete WP posts & tags once done,
- ability to cron imports.
This would allow the use of some plugins on WP that do not exist on Joomla! to fetch content and inject in Joomla!