I haven't used my Mophie battery pack to charge the iPhone even once. The battery usually lasts all day.
Much, much faster than the 6s.
The taptic feedback engine is great and adds to another dimension to the UI.
Do not stress since its waterproof e.g poolside, beach, on the table etc.
Love looking at the matte black finish since most of the time the phone is flipped on its back in silent mode while working.