I understand that they do cost a bit more than the lead does. They are @ $1-1.25 per weight. Out of the last 3 years that I have been using them, I have only lost 3 of them. 2 were due to snags in underwater brush, and 1 was due to the glue wearing off in the center and the weight detached from the swivel.
I have provided a link on a Tech Report that I found online. It will give you a visual on the weight and how to rig it. I rig it with a slider attached to my main line, above the swivel to my leader.
Bouncing Betty Link I almost forgot to add: I believe that my success rate had improved due to the presentation of the bait. The bouncing betty is rubber and "bounces" off the rocks as it flows down the drift, instead of dragging along. I think that it presents a more natural flow than the dragging lead. I dunno if that's what it is or not. I do know that I still use all 3 methods for weight, depending upon river flows and location. But I do seem to do better with the BB as opposed to the other 2 methods. Just a thought.