I'm currently using Django evolutions to manage my product's database evolutions. It's not perfect but I've learned to live with its flaws. For instance, I always have to copy my production database to test before moving out a new schema because the "evolve" command cannot always evolve a database that was changed in several small migrations (on test I did A->B->C, but A->C will not evolve correctly.)
Will South fix all of those problems? Is it worth the effort of learing a new tool?