Which camera gives more accurate image, the front or the back camera?

My phone is Kyocera Hydro Icon with Android 4.4.2. I use its back and front cameras to take pictures of my head and face at distances around an arm's length. I found the front camera gives more pleasing pictures than the back one, for example, the pictures taken by the back one often shows my eyes are proportionally smaller. Also the front camera seems to produce completely dark pictures when the lighting isn't good, while the back camera can still produce clearer pictures. Which camera gives more accurate or realistic pictures of my face and head at distances around an arm's length?