There seems to be a few reviews on these fins from the forum on the dark side. The thing is that I would take advice from that demographic with a grain of salt.
I went for a surf the other day (4-6ft reef break and juicy) and my board (a 6'2" Simon Anderson ) was super smooth and it surfed really well in the pocket, I think the Quobba fins lift the tail a bit and this translates to a fast smooth turn but you need to push it hard to get the most ouyt if em. also I lost one of the side fins on the reef so I need a new one.