I have an Icon 6000, a Stone Glacier Terminus, and a Kifaru Bikini/Timberline 1. The Icon is certainly well built and comfortable. I have hauled up to around 80 pounds in it, and the load lifters are fully functional. I like the pack quite a bit. It does not seem as durably constructed as the SG or KF. I have had good experiences with the SG and KF for hauling 100 plus pound loads as well. It seems there have been some improvements to the latest Icon models.
Still, the Carbon is exposed and subject to chipping or cracking. Just something to keep in mind. Kuiu packs are nice lightweight packs, but I recommend taking a look at the other options as well.