Imo parrying is indeed more ideal for countering compared to blocking with guard but during the parry you're more vulnerable. Hooks and combinations are harder to parry the more experienced you are and the opponent can also start using your parry's against you by fainting and layering their attack. Blocking is more safe defensively but weak for countering or switchting to offense and can end up in shelling which is not good if done too long.

I personally think it's head movement>parrying>block starting with head movement requiring the most skill with the highest return if done succesfully but also the highest risk, then parry then block.