I initially had issues with the beta versions (I know they were beta) but they were very quickly resolved by Billy the developer. It's rare that you run across a developer that has put so much time and effort into ensuring that the product does what it says and works in your environment. Billy really went far and above in getting WP4J running in my environment.
I can't say enough about how good the implementation actually is. You are really running Word Press from within a Joomla environment.
If you want the ultimate blog environment and your site is running Joomla this is the extension package for you.