Apple

The Apple iOS is exclusive to a range of Apple devices that include the iPhone, iPad, iPod Touch and Apple TV. The user interface of the device uses direct manipulation using multi touch gestures.

iOS hails from Mac OS X, with which it shares the Darwin foundation, and it is consequently a Unix operating-system by nature. 

The iPhone featuring the iOS was one of the first smartphones controlled mainly though its touch screen and the first phone to use a multi-touch interface. The device also featured a web browser that was much better then its rivals.

The OS is closed and proprietary in nature which has gained criticism. There are some issues with restrictions imposed by the OS which locks purchased media like music or movie's to the Apple platform. There are yearly subscriptions needed to distribute apps developed for the OS and general control and lockdown of the platform. 

More alarmingly is Apples ability to remotely disable and delete apps from devices at will.