The Controlled Feed has 2 things the tang safety action does not.
It controls the round from the magazine to the chambef and it has a fixed blade ejector. They all have the non rotating extractor.
If the rails and ramp are set up right, they all feed good. But the fixed blade ejector is a serious plus.
As the bottom of the bolt face is open on the Mk ll action it makes cleaning the crud off/ out of the bolt face. Plunger ejectors and rotating extractors can cause problems in cold wet conditions.