It is my understanding ball diffs are less prone to diffing out by design. The friction between the balls and the main diff gear under heavy acceleration/braking will create a sort of "locking" effect. In gear diff terms, it's like having a thicker fluid under acceleration/braking but a lighter fluid off power.
With that said, I've been running an sc10 gear diff in my buggy for the last 2 years with 2k diff fluid and the car runs just fine on a med bite clay track. I have been thinking about switching back to a ball diff just to try it again. I only switched to the gear because it was cheaper after I chewed up the outdrives on my ball diff.