The protective film be harmful to the display quality is not noticeably, the Touch is easy to operate as before. The fingerprint recognition of the S5 seems mini to work a little worse, the sensor (control knob) is indeed spared, but the protective film is a bit thick, so you do not so well in the "gap" is the finger and thus the contact with the sensor less intense is. I think with a little practice, this will also improve, so full marks.