Thanks for the Amarok description Pete, I am considering getting one, so quite relevant. Also interesting to read that you prefer using spearguns which can be used 2 handed.
...The Nemrod Elliptic gun is fitted with mono shooting line which I don't like as it is springy stuff and I have a mind to chop it off and replace it with dyneema. Mono is fast through the water, but one nick and it has to be replaced as a big jerk and it will just pop...
My old speargun was equipped with Rob Allen's robust/tough 2mm black Mako line (rated at something like 200lb-400lb?). It aquired an impressive array of nicks and gouges over the years without needing replacement, as UK fish rarely approach 1/10th of the rated poundage. I did replace it eventually but could have probably used it for several more years before it became critical. I use thinner spearlines these days; Omer's black mono seems pretty tough but being thinner needs replacement if it gets much of a gouge.
I gather from Foxfish that there has been some discussion about the possible advantages of using thinner mono or Dyneema spearline in reducing drag on the spear. I missed that I'm afraid but I note that Foxfish is now using thinner mono spearlines, so I assume he was convinced or, at least, intrigued enough to try it.
I am a fan of Dyneema/Spectra/Kevlar for wishbones, constrictor cord, lure fishing braid and climbing gear but not so keen on the idea for spear line or speargun reel lines. I really like mono spearline, it just seems ideal to me (cheap, range of diameters/colours, just the right combination of flexibility and stiffness, smooth,strong, light, etc.). I think perhaps the thought of expensive, thin, soft cord, which is significantly harder to cut with a knife, floating around me in a tangle in the water is not an attractive or necessary option. Although even cutting that RA Mako line mono would likely be a challenge with my rather crappy 420 steel dive knife