...
The use of beta-versions for production systems is generally discouraged. The parallel build functionality is brand new, and although they are tested with quite a few projects they do not have the general wisdom accumulated by running on multiple project types on multiple platforms within the community. So take care.
Plugin/Settings compatibility
...
There is a bug in plexus io that causes all the jar/war/ear plugins to intermittently fail with output on the form "Failed to retrieve numeric file attributes using: '/bin/sh -c "ls -1nlaR <a path>" (Maybe linux issue only; might be related to http://jira.codehaus.org/browse/PLXCOMP-122 ; may also be related to localization of linux)