Allyson Kazmucha, writing for The App Factor, lays out six specific uses for 3D Touch on the iPhone 6s that make a world of difference. This is a solid list, well described, and worth reading if you have a new iPhone 6s or 6s Plus or are considering a purchase.
6 reasons I couldn’t live without 3D Touch ever again
I didn’t know about the trackpad feature on the 6s! Awesome.