In reply to d_b:
I have a couple of the aramid ones. They're good and I quite like them (good for pokey threads) but there are a couple of disadvantages to them.
As someone else has said, the stiffness of the 60cm makes them not ideal for extendable draws.
The stiffness means they're not very good for clove-hitching runners onto quarry spikes, rock-anchors, etc. that you often come across in the quarries/gorge.
The 120cm ones seem to come up a little longer than your standard 120cm sling, which means if you shoulder them like I do (clipped over the shoulder to a krab) that they hang annoying long. If you just double 120s up rather than this method, then they're fine. I don't like doing that because of issues getting them off when I need them. I think they'll be okay clipped with a krab for winter use, as the extra layers of clothing will increase my girth.
They don't knot as nicely as a flat sling or regular cord does, but that can be seen as both an advantage and disadvantage.
They definitely handle a little better than your standard sling, and feel a bit more abrasion-resistant (which increases confidence in chucking them over sharp blocks or through threads).
The other big advantage of them is that they are a lot better when exposed to UV. The strength is in the core, so the sheath stops them degrading in sunlight like a nylon sling would.
One thing I would be interested in (since the core is an alien material to me), is how well it wears. From my understanding, dyneema cord needs to be replaced more frequently than nylon, as repetitive movement wears it down more quickly. How about this 'aramid'?