I agree with John, it's all a matter of what you're trying to get done. I fish smallies and need to get my large flies down deep quickly. I use flourocarbon because it works best for this type of fishing. However, two winters ago I found a spool of 2 lb. flouro (thanks to winter ice fisherman up in this neck of the woods) and furled up a few leaders. Liked suppleness of the finished product but was disappointed when I started fishing it. It didn't turn over the bigger flies as nicely as my 4 lb flouro furled leaders. My 4 lb flouro leader lasted all of last season and I put many, many hours on it.