Mantle makes it easy to write a simple model layer for your Cocoa or Cocoa Touch application. Core Data solves certain problems very well. If you need to execute complex queries across your data, handle a huge object graph with lots of relationships, or support undo and redo, Core Data is an excellent fit.
Blinged JSON Validator is a free app to validate JSON files with syntax highlighting, whitespace indentation, error messaging, and hotkeys.
