I'm not addicted to it probably because me and my clan decided to take a break from competition. So it feels like I have no addictive passion to train and get better like before... I've been only playing zombies on BO2 lately... LOL! (until I get sick of it because it becomes repetitive for the day or even week).
I'm sure they've gone through many fixes and updates since I've stopped playing in multiplayer. But when BO2 came out, I just didn't like many things. Example, when my teammates rage quit, it took like forever before others join in. Happened all the time when I played. Or if it happens to the enemies (I usually roam around calmly until the enemy team gets enough players before I jump in to really play). Been roaming around for a long time, sometimes even went to take a dump!
Also I liked the explosive-spawn-protection in MW series. It prevents extreme spawn killing (for those who abuse spawn points with explosives or some killstreaks).
But all that aside, I loved the graphic improvements in BO2. The sound too. Everything was smooth.