I have been using Xcode 4 for 2 weeks and I noticed that I don\'t get code completion macros for if-else and switch statements.
Like this article describes: http://macd
Have you tried deleting the project's derived data (which contains the project index used by Code Sense)?
To do so, open the organizer (Window -> Organizer), then the Projects tab. Select your project then hit the delete button next to the derived data path (to the right). Confirm and let it re-index your project.