The new audio dub for Alien 3 SE is very good. Not only has dialogue been re-recorded, but new sound effects have been put in.
Things like Clemens' footsteps on the beach, the oxen making noises, the bed creaking when the alien attacks Clemens in the infirmary and the aliens' screetching when Junior sacrifices himself.
One annoying error is dialogue from Murphy calling for Spike (the dog) during the air vent scene on the Special Edition when the dog isn't in that cut.
This was also an error on the Region 1 Quadrilogy DVD that was corrected on the Region 2 version, but it seems to be on all Anthology blu-ray editions.