I'd get BF4 over Ghost. For someone who has both of them, i'd say I have the experience of playing both them besides just reading reviews or etc.
BF4 is better in multiplayer as it has the big map which can play with a huge number of players which is 64.
Multiplayer experience is just great, considering it has a lot of assignments to unlock weapons and accomplishment for recognition for replayability.
All those heli, tank, bike, jetski, boat and others are fun to play with too.
The only downside is the campaign which is ok up until the ending haha.
For Ghost.. Multiplayer wise is super boring
Same number of players like last time, small map and well just same old BO2.
But the campaign is awesome, as the story is very interesting.
If you really are into this game just get it. Multiplayer for BF4 will suck a whole load of hours like probably 200+ or 500+ hours of game time.
If you don't play that much don't bother la

Great advice. Will definitely consider your comment. By the way, BF4 now is also having a sales with Digital Deluxe only at USD38 (50% discount). Both also very tempting.