[williamhj]

I'd guess the majority have used them. It's a very popular and effective fly. I've mainly used them fishing for bass but also for trout. What kind of fishing are you doing? That will help people offer pointers. I've generally cast them across the current (towards the bank) or slightly upstream, let the line come taught, then swung them down and below me perhaps with a bit of a strip so they swing through likely holding areas. There are many other ways to fish them depending on your target species and type of water.