The Guvnor (BRMS) and Eclipse synchronisation tool has made leaps and bounds in progress for the upcoming 5.0 Milestone 2 release. It now has full bi-direction synchronisation of files between Eclipse and Guvnor. A developer can now work locally with a rule, or other Guvnor assets, they can do lots of small commits to their SCM of choice and when they need to can upload or synchronise that asset with Guvnor. Eclipe diff viewing is also supported.
Synchronisation
Diff Viewer
Version History