Still the Best
The review from "Clartikus" below is mine, and I just wanted to post a quick update. This carrier still looks like new even after frequent use and abuse - we use our KCIII weekly during the summer, and it provides a lot of room for baby to grow. The build quality is excellent, the colors and materials look sharp, and we couldn't be happier with our purchase.
A friend of mine purchased the Osprey Poco Premium, and I got to run it through a few test hikes to see how it compared to the KCIII. There are definitely a few features on the Osprey that I would love to see integrated into the KCIII (such as the padded frame to prevent your child from being squished if you fell on your back somehow; the detachable daypack; the diaper-changing pad; the nice soft material throughout the cockpit; and most importantly the extra packing space available by extending the kickstand). While these features are definite wins for the Osprey, I still prefer the KCIII for safety (they are equally comfortable to wear and both have high build qualities). The higher headrest on the KCIII is what sells me on the Deuter over the Osprey - it's just safer, does a better job of protecting my babies' heads from low hanging obstacles and any spills I might take.
I'm very impressed with both packs, but we've purchased two KCIIIs and loved being a double-Deuter family. If we bought a third, it too would be a KCIII.
I'm glad to see so much innovation in this field - things can only get better from here! :)