There has been a lot of talk about which is better for each person.
This is from a magazine article. There will be some who do not agree with this (myself for one cause I can cast a WF better) but, the mechanics do support this.
Flyline Tapers
Or, no, that’s not just an expensive piece of string
By Buzz Bryson & Paul Guernsey
If all fly lines of a given line weight weigh approximately the same, in grains or grams, then why would one line of any particular weight–a 5-weight, let’s say–cast any differently than another? In other words, is there really a difference in the performance of 5-weight fly lines from maker to maker, and model to model?
There can be significant differences from brand to brand and model to model for a given line weight (forgetting completely those differences attributable to densities). Remember that the line-weight standard is based on nothing more than the weight (in grains, as you pointed out) of the first 30 feet of the line, not including the level tip. Beyond–or past–that, manufacturers are free to taper the line as they wish.
Let’s start by looking at the most simple example: a couple of different level floating lines. What differences could there be? Well, first of all, while the weight is nominally the same, there could be slight differences in density, and thus diameter. A less dense line would float higher but, being larger in diameter, it would be more wind-resistant during casting.
Now, without changing the weight of that first 30 feet, but merely by redistributing it, let’s add a taper to the front of one of those lines. Suddenly, its casting characteristics change radically. A short, steep front taper will turn over the line quickly and surely–just the thing for plunking heavy nymphs. A long, gradual taper will land the fly softly; just what’s needed on flat, skinny water for sippers.
In fact, taper designs are now so sophisticated that all the manufacturers now sell many different lines in the same line weight for both general and specialized uses. For instance, that 5-weight you mentioned is available in “general purpose” tapers–but also in tapers specifically designed for heaving nymphs or streamers, and others for wafting tiny dries. The former typically have shorter heads, steeper tapers and heavier tips, all to facilitate better turnover of heavier flies with less false casting. The latter have longer front tapers and lighter tips, for light presentation. Both types can be found in your hypothetical 5-weight, and their performances are remarkably different.
In addition, manufacturers also use different cores and coatings, which affect stiffness and slickness, and thus casting. Stiff cores are used in hot weather, such as flats fishing, when normal lines tend to “wilt” and droop between rod guides, reducing casting distances. Conversely, when using that stiff line on a trout stream, the angler will find it really tough to keep the line straightened, and a kinky line is tough to cast, mend and keep afloat. --B.B.
What’s the difference in casting performance between weight-forward and double-taper fly lines? Under what circumstances should an angler choose the DT over the WF?
In order to avoid having to write a book here, we need to control our variables. Let’s assume we’re comparing a WF and a DT that both have the same tip, front taper, and belly–at least until the point at which the belly of the WF ends and it transitions into the rear taper /running line, while the DT’s belly continues on. Let’s further assume the head length of the WF is 30 feet and, for discussion’s sake, that we’re talking about a pair of 6-weight lines.
For the first 30 feet of line there will be no discernable difference between the two lines. However, at casts of 40 feet or greater, things begin to change. First, you’ll find the WF harder to control: Anything less than perfect timing will result in difficulty handling that much of the thin running line outside the rod tip. Second, you’ll feel the rod with the DT load more deeply. With that 10 extra feet of belly extended, the DT will increase in mass by roughly one line weight: At 40 feet your 6-weight DT line is now equivalent to a 7-weight. But that extra 10 feet won’t add quite as much to the WF line, and consequently won’t load the rod as much.
There’s another difference you should be aware of: While the 40 feet of DT will rollcast fine, the WF will give you trouble. Same reason: The 10 feet of lightweight running line outside the tip doesn’t have the “guts” to turn over the fatter belly in front of it.
When to choose which type of line? It makes no difference for shorter casts. For longer casts, and when you prefer to aerialize only 30 feet or so and shoot the rest, use the WF. Its head will carry the light running line better (farther). But if you like to aerialize a lot of line so you can precisely determine the length of your cast and not shoot as much, the DT offers more control.
–B.B.
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so I’m not going to be buying multiple lines to try them all out. So I guess it sort of doesn’t matter right now.