Basically there’s a shitstorm of negativity around the gaming websites etc. about the Xbox One in relation to the PS4.
Mainly this seems to stem from 2 3 things:
1 – The Xbox One is on paper technically less powerful than the PS4. Both have the same processor iirc, with a slightly weaker graphics chip in the Xbox. PS4 has 8Gb of GDDR5 RAM, Xbox has 8Gb DDR3. Whether or not this technical difference will translate into a real world observable difference in the presentation of cross-platform games remains to be seen.
2 – The perception that MS has abandoned the core gamer’s desires to chase its dream of integration with TV and becoming the home media hub first and a games machine second.
edit: 3 – The whole fiasco around their refusal so far to clarify exactly what their pre-owned games policy will be and how it will work.