Actually ComponentKit is built on GCD!
https://github.com/facebook/componentkit/blob/master/Compone...
GCD is fantastic—one of my absolute favorites. We're trying to solve a problem one level above that: exposing an API that doesn't require every view developer to know the details of managing GCD queues and updating a UICollectionView.
As for Autolayout, it's very powerful but isn't performant enough for layouts as complex as Facebook's News Feed. We tried it first before developing ComponentKit.