It was good, a major improvement on Black Ops 1, that was a massive dissapointment.
At least it had a plot behind it, too many games nowadays contain a so called "Campaign" even though they seem to just be missions with no background.
I did enjoy the missions on BOII that were set in the past mind you, the missions in Afghanistan/Panama etc were good.
My favourite mission of any COD still hasn't changed though, All Ghillied Up from number 4 still tops them by miles for me, stealth missions all the way.