I have asked this question a few times, the response is a 50-50 mix. Copper is a bit more temperamental, but it is much stronger. You will never break off 45 pound copper. Personally I have 4 copper setups and 4 core setups. Copper runs deeper, but likes to backlash more. The coated copper is much better, than the non coated. What I have noticed when letting out copper was, in shallower water it would sink to the bottom and hook mussels before the board pulled it out.