In terms of singleplayer campaign, Black Ops 2 wins by a landslide. I'm not saying Black Ops 2 has the best campaign in the entire history of video games, but it provides more options and story to the player than Ghosts's campaign.
In terms of Zombies vs Extinction, I can't really say who wins.
Multiplayer, however, is a tough subject. With Ghosts, I like the sliding-to-crouch better than Black Ops 2's dolphin diving. As well, the contextual cover system is a plus and the dynamic map events are alright I guess. However, Black Ops 2 has killstreaks that are way more fun to use, the guns are more fun to use, and I like its maps much better.
Black Ops 2 maybe better probably owing to the fact it is an older game in the Black Ops franchise and has therefore been allowed more time to develop in areas like downloadable content not to mention the bigger fan base that it should have from being out longer so therefore having more players in multiplayer lobbies.
I have only played the new COD a couple of times; but, from what i have gathered, Black Ops 2 is the all around better game. I think it has better maps, more game modes to play with, a smoother running online multiplayer, and of course, zombies; which can be a game in itself.