You can take photos with voice commands, like "shoot". Palm swipe on the screen to do a screen capture. Lifting the phone to your ear while viewing a contact's details, message or call log will initiate a phone call to that contact. The alarm clock will play your selected alarm sound for a few seconds, then will "say" the current time, current weather and the day's forecast, any appointments you have that day, and the top news headline. Of course, any of these and other features can be disabled.
I also like that with the GS3's stock launcher, the app drawer can be configured as an alphabetical list with letter "hot keys", similar to WP7. You really appreciate how intuitive this is compared to searching for an app through pages of the traditional Android/iPhone app icon grids.