NOTE: Sony has since changed their calibration to being similar to previous Sony devices. The gamma response is a noticeable S curve, which intentionally makes parts of an image “lighter” than they should be.
I compare the displays of the Xperia Z2, Galaxy S5 and HTC ONE.(Z2 Display review) The Z2 does an impressive job! What I say about Color Management is horrifically oversimplified ON PURPOSE. Please see: http://www.cambridgeincolour.com/tutorials/color-space-conversion.htm
Z2 First Impressions: https://www.youtube.com/watch?v=dviYRetmjTQ
Please follow the display Guru himself!