It's really a personal preference kind of thing. I suspect most spearos will stick with whatever type of wishbone they used when they first learnt to spear. I started spearing with a Rob Allen railgun. These South African railguns are equipped with Dyneema cord wishbones. I find them much less intimidating than the knife-edged metal wishbones fitted to most European spearguns as standard - such as the otherwise excellent articulated Omer wishbones fitted to your and my Omer XXVs.
I've never cut or injured myself using a Dyneema wishbone, despite using them extensively. However, I did once cut my finger and glove quite badly using the metal wishbone mentioned above, despite using it far less and having considerably more experience loading a speargun by then. Admittedly, I made a mistake trying to load quickly having seen a large fish after unloading as I approached the beach - but it wouldn't have been much of an issue with a Dyneema/Spectra cord wishbone.
Dyneema wishbones are generally (but not always) fairly cheap & simple, if you shop carefully and/or make your own but, as OldManDave pointed out, his metal wishbone was still going strong after 13 years (I changed my Dyneema wishbone once or twice in 2-3 years). Dyneema wishbones can last years if used carefully but once fouled or worn, you generally want to replace them, even if they are still mechanically sound - just in case.
They are the obvious choice to use with (inexpensive but good) bulk rubber, which has no threaded fitments. Using bulk rubber is generally cheaper than buying name-brand threaded rubbers - and you don't have to worry about whether Picasso threads fit Omer rubbers (they don't, in my experience).
I like the simplicity of a cord wishbone. Oh, and its quite a bit lighter too (unless you use the heavy metal toggles from spearitco.com
), which can complement an ultra-light gun/set-up, like the XXV that you and I use. Oh yes, its quieter and less likely to scratch your (lovely carbon) barrel too
.
So I guess the advantage is:
(1) less chance of you/your gloves being cut
(2) peace of mind from (1),
(3) the obvious(/only?) choice if using bulk rubber and
(4) light & simple
(5) quiet
(6) non-scratching
Disadvantages:
(1) not necessarily cheaper. And, if you already have a metal wishbone, the cost will be an unnecessary extra expensive.
(2) they don't generally last as long, so you'll need several & a special tool to insert them (or needle nose pliers).
(3) Can break while spearing - spoiling the dive
. There are ways to reduce the impact of this, such as: double cord wishbones, toggle loops that allow a new wishbone to be tied in the water (hah!), carry a spare speargun (e.g. on the float, on the beach with family or locked out of sight in your vehicle), check the condition of your wishbone & the notches on the spear before each foray.
(4) You must
ensure that the wishbone notches/grooves in your spears have there edges smoothed and polished, so they do not cut the cord, nor its protective sheath. Rob Allen spears come like that, most other spears don't. So expect to spend some time and money (on tools) to do that.
(5) Might affect the factory-set accuracy/balance of your speargun.