In his new podcast, Tom explains the difference between braided-monofilament and furled leaders, and offers some expert insight on why you might want to stick with nylon in standard trout leader setups.
"I use nylon leaders for most of my trout fishing, because they float better than fluorocarbon, and most of the time I don't want my leader to sink too much. If I'm fishing a dry fly, I don't want it to pull the fly under. If I'm fishing a nymph, I want part of my leader to float so that the front of my fly line floats so I can see a fish strike. Also it's easier to get a drag-free float."
On braided vs. furled: "These leaders are constructed in different ways. Braided leaders are made up of many tiny filaments, and they're hollow inside -- the filaments are braided around a hollow core. Furled leaders are slightly different in that they're a solid core, made of a bunch of filaments that are twisted together."
Oddly enough, I became very happy with braided mono leaders from FeatherCraft on my two 8 weights. I tried a Rio mono leader after 2 years of the braided or furled leader (not sure which it is). After a few weeks fishing, I went back to the braided jobbie. It just did a better job at keeping a tighter loop and turning over my fly. It's pretty burly and heavy, so I made a stepped tippet, going from 15 lb fluoro to 10 lb. fluoro. It helps turn over Clousers pretty well (actually, such a heavy fly is more 'assisted' or 'guided' by the leader and tippet). I'm happy with it.
Regarding the ability of a furled leader to produce a uniformly tight loop, I suggest thinking of a bull whip. Wouldn't you expect a single, tapered bull whip to turn over better than a whip (if there were such a thing) made from braided lengths of leather of diminishing sizes, joined by knots?
BB