Advanced Warfare is my favorite personally, it feels more like if Titanfall 1 had a campaign... and that's awesome. Infinite Warfare is very cool but the spaceship missions lose their novelty fast I thought. Modern Warfare 3 has a lot of awesome urban city sections in Europe I believe, really enjoyed that one too. And I liked Ghosts' despite what most say, apparently. I played all of these years after their release and so went in pretty fresh on them all, had fun.
On the flip side, there sure does seem to be a lot of Black Ops fans, but I thought they all sucked. Was even shocked at how low budget Black Ops 3 looks and feels compared to the Infinity Ward games, even stuff that predated it like Ghosts or Advanced Warfare look way better. Didn't even bother finishing 2-3. Awful stuff.
I'd like to pickup MW1 remastered eventually whenever it gets cheaper. Shame they changed things about the multiplayer though, for the worse from what it sounds like.