I'm not usually a carbon fibre widget guy. I tend to err on the side of quality and longevity. So when I bought this carbon crank of eBay it was because it was the only octalink compatible compact crank.
I had been running a Dura-Ace 7700 crankset with 39/53 gearing. I need some gears for riding in the mountains so hence the compact. The new crank weighs 543 grams and the old weighs 603 so I end up saving around 60 grams. Whoo-hoo!
That monstrous savings amounts to a free snack.
Carbon while it can be made über light it usually is only marginal on a single part.