How do I sync all my apple devices?
 iCloud

— What it does do —


synchronize (only over iTunes bought!) music if specified
synchronize pictures (photo stream)
keeping track of your device-location
backups of your device


— What it doesn't do —


synchronizing application data UNLESS specifically implemented by the app
keeping applications in-sync — this is due to different device classes have different preferred applications. For instance, you usually use different apps on an iPad as you would on an iPhone