Since both Mamboforge and Joomlaforge have times where they are less accessible, I thought having uddeIM at both locations would be best, especially since it runs under both Mambo and Joomla.
For bug filing, feature requests I wanted to have only one - so these things are disabled at Joomlaforge. Mamboforge seems to be a lot easier for novice users. I monitor both Mamboforge's and Joomla's forum.