Implementing the first two syncing approaches isn’t easy, but developers tell Macworld that the third approach, for syncing Core Data, is what Steve Jobs might call “a bag of hurt”—it’s extremely complex. While iOS 6 will offer developers some significant improvements for behind-the-scenes iCloud syncing, the challenges such syncing presents will likely remain difficult.
Are there any applications from Apple that use Core Data iCloud syncing?
Update (2012-07-24): Or, Matt Stevens asks, Core Data at all?
Update (2012-10-26): Troy Harris and Reddit on Core Data and iCloud.