Streamers are definitely effective in muddy water. But they work quite fine in cold, clear water too. The past two Sunday afternoons, I fished streamers in those conditions and caught eight fish. The streams only have wild browns (at least as far as I've ever caught over the years I've fished them). In the wintertime, I fish micro-buggers like big nymphs (often on brookie streams). On the streams I was fishing the past few weeks, I was fishing a bigger streamer and it's a lot of fun fishing a lower, clear stream and watching the bigger browns come out of their hiding places and chase a streamer in some cases right to your feet.