There are a few places where you discuss how to order to-many relationships (using sort descriptors). My understanding is that 10.8 and iOS6 support using NSOrderedSet instead NSSet for loading children. The only mention that I see of this is on page 127, where you mention that iCloud does not support ordered relationships.
I would like to see a short section that specifically addresses how to create the ordered relationships that iCloud supposedly doesn’t support. Ordering appears to be a relatively commonly requested feature and question (judging by Stack Overflow).