Many use it. I did a small, informal survey in a Danish flyfishing Facebook-group. Out of 60 replies, 35 used FC, 25 nylon. It would be interesting to do the survey again, because at the time, I think it was still possible to get 12’ FC leaders, and out of 45 replies on leader length, 20 used 12’ leaders (+ tippet), and 12’ fluorocarbon leaders are no longer in production.
We’re told that nylon degrades very fast in tropical environments, because UV breaks it down, and FC doesn’t. And while I’m sure that is true, I’m not entirely sure how big the problem is. I mean, people have been flyfshing the tropics for decades before FX became available. But still, I know experienced anglers who say that the problem is noticeable, and who would *never* use nylon in the tropics.
FC also sinks, and some claim that makes it useless for dryly fishing. I find that a huge advantage and sometimes, if conditions are really difficult, I’ll all FC tippet to my leader when fishing really small flies on long, thin leaders in clear, smooth water. I can’t say that I have positive experiences that it makes a difference, but I can say that the tippet sinks, which is advantageous. It’s generally not difficult to make nylon sink with a little Fuller’s Earth-concoction, but the very thin ones can be a little difficult to sink - especially with a fresh tippet. Generally it’s not a problem.
The biggest showstopper for me is the way FC casts. It’s very stiff in the think section of the leader, and it’s obvious to me that it causes the leader to rise up in the air, rather than turn over in a loop. This is especially obvious when you’re not casting the highest linespeeds. High line speed and big(ger) wind resistant or heavy flies minimises the issue, but dones’t necessarily eliminate it. In my hands, nylon beats fluorocarbon hands down in “castability”.
FC is harder and stiffer and so more abrasion resistant - I’m sure that’s true, and there are probably situations where that makes a difference. I’m fairly sure I haven’t had a leader snap over a rock, a log or something else, where I think FC would have stood up to the test, but that might very well be a rationalisation after the fact.
Some also use it for pike and other toothy critters instead of wire - claiming it’s harder for the pike to see. I’m not sure that’s true. Wire comes quite thin these days, and in order to be just somewhat on the safe side, you need to use at least 0,80mm FC to avoid the pike biting the leader off. I’ve made some pike leaders with FC, but I have yet to find the reason/conditions to really test them.
Of course the whole invisibility-under-water was a big selling point in the beginning. I don’t really know where I stand on that.
I generally go though a handful or two of leaders during a season (wear and tear, the occasional wind knot, changing between lines etc), so it’s not that the price matters as such, but still, nylon is generally half the price of FC, and that goes for both leaders and tippet material.
I’ love to hear your preferations in this thread on the Board. I'm enough of a victim of the marketing that I often carry a few FC leaders and a couple of rolls of tippet, just in case I should feel it can make a difference...
Have a great weekend,