Both the Xbone and PS4 are woefully short of games at the moment, but while I cannot comment on the XBone, I can say that there are a reasonable selection of free games on the PS4 if you have PS+ membership (its essential now as its the only way you can play online with most games now). Contrast and Resogun are both free to members, but am not sure of their rating (Resogun is an old style sideways shooter so should be fairly low rating). Then you have the free to play games Blacklight retribution, Warframe, War Thunder & DC Universe Online.
All free to download but you can use micro transactions if you want to buy things in game. Of these, only Warframe and Blacklight might be higher rated.
DC Universe is actually the same game available on the PS3, but they did a small graphics upgrade on the PS3 and PC versions before the PS4 version was launched so it looks a little better, and I think is cross play, so you can still play with people on the PS3 as well.
These 4 free games may require PS+ to play online, but I dont know for sure as I have been a member for a while now.
None of these games would be deal breakers though as to whether you buy a PS4 or not as none of them are amazing, but are good at least.
