Got my Ps4 on nov.15, have been playing it way too much.
I currently only really have Resogun, flower, BF4, gf paid AC IV to me as a bday gift Dec 30th but took it back and wrapped it up and will only give it to me on xmas. I'm okay with it, can't really put the time in a long game at the moment.
and for the BF4 vs COD thing, IMHO, on next gen, BF4 is Far better but it suffers from a lot of bugs, they released it way too early. It's just starting to get more stable.
BF4 and COD the multiplayer is similar in difficulty but the Single player COD4 is much harder, I just went through BF4 single player at the hardest difficulty and it wasn't very hard.
however BF4 is much more diverse and interesting, you can do the good old SnD, Team deathmatch and all just like you would in COD or go in a massive Tank\Chopper\planes 64 player battle if you wish too, so crazy different than COD, it's really nice to play. I only really miss the killstreaks, that was fun. On the other hand I can go and jump in a freaking tank and blow **** up right from the start of a game.
Also nothing beats the first time you just go through a freaking building with a tank because you tought : This wall is going to stop me eh. and It Did not. Or you Blow up a hole in a building with C4 to open a new access in a building or just to make it fall... So yeah, BF4 also feels less arcade-ish, more realistic somehow. Anyone playing COD should give BF4 a try but on current gen they're going to be very similar and the graphics aren't too amazing on 360 compared to PS4. the leap is amazing, however no internet video will give it justice since there's a huge loss in quality because of the streaming process.
So far my PS4 has been amazing in most aspects. Even the controller is amazing, I prefer it over my 360 controller but the battery life could be better. It's still fine though I have a second controler so I just turn one off and use the other one while it's charging.