PS4.
It has a bigger library of games and a larger number of games that are +70 on Metacritic. Those are about the closest you're going to get to an objective assessment of the quality of the game library. The rest of it is simply personal opinion, which of course is mostly reflected in the buying choice of people here. And that is fair enough,
People tend to focus on the big AAA exclusives, but in both cases that's a mere handful of games right now, and many of those games on both platforms have ended up being underwhelming or downright disappointing. I don't mind admitting that Xb one has a slight edge there most notably with Titanfall (not an Xb one exclusive but it ain't on PS4) and with Forza. But that's not the full story and if you are looking at game library then all available games have to be taken into account. 3rd party games have been better on PS4 in the vast majority of cases; even if only slightly better, better is better. And the indie / PSN library on PS4, is looking great.
“The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt.” - Bertrand Russell
"When the power of love overcomes the love of power, the world will know peace."
Jimi Hendrix
