Windows RT 8.1
You can add widgets to the home screen. This allows you to have more flexibility and to see information at a glance, without going into the app.
The web browser has automatic word wrap when zooming, the user can easily read long lines without scrolling horizontally.
With a search browser application you can surf the internet from your device.
It can be updated over the air (OTA) w/o connecting to a computer
All your contacts and calendar dates are synced over-the-air.
With a large enough data plan, you could cancel your home internet and use the device as a hotspot.
NFC (near field communication) allows a device to perform simple wireless transactions.
You can easily manage notifications by adjusting your preferences, and you can also turn them off completely for specific apps.
The OS has a feature for tracking the position of a mobile device. This feature is particularly useful if your phone gets stolen or if you lose it.