This topic has been discussed since the beginnings of fly fishing. In the world of Steelhead fishing, my personal preference is as follows: I would rather fish a weighted leader and a non-weighted fly because the fly behaves more naturally without weight. It has more animation/life and follows the currents more like a living thing. However, sometimes weighted flies are necessary and can be used effectively on a sink tip or with a long leader on a floating line. I am curious to hear other opinions. Please let me know.