Recommending food is such a brave thing to do (yet we do it anyway) because people have very individual tastes and the mood and company that you are in can very easily influence your perception. For what its worth, I rate the Dagwood Steak Burger at Primi Caffe in Durban as my current favourite burger in Durban. Here's my review.
My review for Durban Live on the Primi Dagwood Burger
It is huge, very filling and very expensive so be warned!