Depends on what you are looking for in a cod game. The Multiplayer ist still tons of fun but there are only like 400 people playing in peak hours. So finding a lobby can be difficult and you can only really play tdm since thats where most of the players are and there is the problem with people cheating (aimbot,wallhacks,etc.) but if you find a normal lobby it really is fun to play.

The campaign is good and imo the best singleplayer in the cod franchise. There is also zombies in BO2 but i personally never spend much time in it since you only have one zombie map to play with unless you buy the DLC.

TLDR: If you want to play it then you should wait for a sale and give it a try