For me, the CF's are worth the price because my work often requires me to pack my climbing gear across the mountain side. I appreciated the change from steel Buckinghams to aluminum Bashlins, and I REALLY appreciated the change to CF Geckos.
Other than that reason, maybe not so much. When in actual use, I notice the light weight, but don't really think it makes all that much difference. I got the medium length, fit me fine. Just measure what you're wearing now, from stirrup to top of shank/pad.
They are cooler than the under side of your pillow, though. I still laugh when I pick one up...feels like it wants to float away.