I second what Stephane said that right now Morphic is the King as far as GUIs are concerned, documentation and available code. Spec is too much a moving target and far from replacing Morphic but its definitely a welcome clean up. �Morphic is too messy at some areas but overall works really well considering anything you see inside pharo is build with it.�

I am also working on a new GUI API using Athens and Morphic. My focus is in custom drawn GUIs which is the exact opposite of Mars native look and some crazy ideas I have about gui design. ��