What X-shaped submarine stern planes offer

What are the advantages and disadvantages of X-shaped stern controls on submarines such as Columbia and KSS-III?

They offer balanced control, maneuverability, and damage tolerance, but depend more heavily on reliable computers to translate helm inputs into coordinated surface movement.

An X-stern distributes control across angled surfaces, offering maneuverability and some control after damage that would otherwise remove an entire control plane. Coordinating those surfaces is presented as easier when a computer translates the requested movement into the necessary combination. Manual control is suggested as a reason to prefer a conventional arrangement. The resulting concern is dependence on a computer that can itself fail. Multiple independent systems with majority voting are proposed as protection against that risk, without confirming the exact redundancy fitted to either submarine class.