The document discusses five main mobile operating systems: Symbian OS, Apple iOS, Android OS, Blackberry OS, and Windows Phone OS. It provides details on the key features and benefits of each. Symbian OS is budget-friendly and continues to be updated. iOS 5 allows wireless syncing to iCloud and includes iMessage. Android 4.0 Ice Cream Sandwich merges the phone and tablet versions and includes new widgets and facial recognition unlock. Android also offers an open platform and affordable devices.