Some anglers lure fish with braid and some don't, and some anglers use leaders at the end of their braid and some don't. I happen to use braid and pretty short fluorocarbon leaders for my bass fishing especially, and over the last few years I have actually ended up using a number of different fluorocarbons that to be honest have all worked just fine for me. Try as I might I can't think of any disasters that I could blame my leader for.
I know that fluorocarbon is meant to be essentially invisible underwater, but in my head I am not really using it as a (short) leader for that reason. Sure, I do tend to like brightly coloured braids and therefore I feel comfortable having a section of clear line at the end of all that colour, but for me it's more a case of not liking tying my braid direct to a lure or a lure clip, and I also very much like the inherent stiffness in a fluorocarbon leader as I feel it helps prevents both my braid and/or my leader from "collapsing" and then tangling around any part of the lure when it hits the water or indeed as you work it say across the surface.
These days I am mostly fishing with around a 20lb braid for bass fishing and with the lures I tend to fish with I can't ever remember actually snapping the braid on a cast - therefore I don't for one second worry about not having a shockleader wrapped around the spool on my reel a few times like we might have with more conventional shore fishing. I tend to feel happiest using a roughly 12-18'' (inches) 20lb/0.40mm fluorocarbon leader tied on to my braid via an Improved Albright knot, finished with a 3-turn locking knot around the mainline. It doesn't fail on me and therefore it gives me all the confidence I need to put the gears on the fish I hook.
Why such a short leader ? Well when I have for some reason or another tied on a longer fluorocarbon leader that ends up with the knot being within the length of the rod before you cast, it then tends to result in my braid sometimes blowing up - which I put down to the leader knot having caught in one of the rings as it flies out. My short leader means that my leader knot is therefore never ending up within the rod rings (i.e. the knot is always outside the rod when I am casting) - but is this "problem" unique to me ? Yes, I could I suppose tie a "knotless" PE knot or something like that, but to me it's just not remotely required for the fish we are fishing for here in the UK and Ireland. I just don't feel the need for a long leader I guess.
Now it's not as if I am getting through spools and spools of fluorocarbon, but I do change my (short) leaders a fair amount, and of course I like to have a few spare spools say for an Ireland trip in case I go and lose one down a hole amongst the boulders (drives me mad !!). So whilst buying fluorocarbon is hardly breaking the bank when compared to say having a serious lure or lure rod addiction (not me), I woke up early the other morning and got it into my head that I would have a look at the prices of the different fluorocarbons that I know I have fished with over the last few years. If it is any help, none of them has let me down in any way, shape or form and I would/do fish with any of them and feel entirely confident.
There is nothing remotely scientific here, but I went looking around online for the lines and prices, and some are much easier to source than others. The price differences may well be because from a technical point of view some lines may well be "better" than others, but for me I still come back to the fact that none of the fluoros I have used with have ever failed me. Note that I have not included any possible postage costs etc. and that I am sure prices will vary depending on where you go looking. Also be aware that prices can be different depending on what breaking strains you buy and that for some of these lines there may well be larger capacity spools available that could reduce the cost.
YGK Nitlon DFC fluorocarbon - 0.378mm/20lb - £12.99 for 100 metres (roughly 13p per metre)
Varivas Sea Bass Shockleader - 0.37mm/20lb - £9.99 for 30 metres (roughly 33p per metre)
Varivas 365 fluorocarbon - 0.37mm/20lb - £9.40 for 50 metres (roughly 19p per metre)
Shimano Aspire fluorocarbon - 0.40mm/26lbs - £9.99 for 50 metres (roughly 20p per metre)
Sunline Siglon FC - 0.38mm/20lb - £14.30 for 50 metres (roughly 29p per metre)
Sufix Invisiline - 0.44mm/20lb - £7.99 for 20m (roughly 40p per metre)
Anyway, there you go. I had not noticed the price differences that much until I looked at these lines, but considering how comparatively little of the stuff some of us use I hardly think the cost is a major issue here - if you were to look only at the price per metre though then the 100m spool of the 20lb YGK Nitlon DFC fluorocarbon obviously is the cheapest, and personally I really like the fact that this excellent leader material comes in a 100m length. All I need not to do is drop the spool down a hole in the rocks and it will last me for a while.