Specific to iPad is a Split-Mode for Safari, so you can have two Safari views side-by-side. In Mail, when you're composing, you can put the compose window to the right side and continue browsing your inbox on the left. Control Center looks the same like on the iPhone, a huge waste of space.
All 3D Touch enabled features don't work on iPad yet, just like on non-3D Touch iPhones. It's stated in the release notes, that this will change and a bit of it works already in the iOS simulator: Instead of a 3D Touch on a received notification (outside the lockscreen) you can pull it down and it displays the same interactive notification that you would get if you would have used 3D Touc.