Power fist or Power weapons on Bezerkers

so pretty simple question . Are Power Fists or Power weapons mor effective on Khorne bezerker Skull Champs? I have heard both ways and i just want a clear answer from a bunch of people all in one place I run into this topic a lot in other threads
mostly it boils down to this
-the sheer power of the fist-
and
-the ability to take advantage of the furious charge initiative bonus-
so which is better?

Sen