CoD 1 was basically the game that got me into FPS games. It was great, even if I do laugh at it when I play it out of nostalgia these days. (In hindsight, the hardest difficulty is actually insanely easy, and ironsights are actually more of a hindrance than an asset, which is pretty funny).
CoD 2 was fun, even though at the time a lot of people thought that they “ripped off Halo”. (Funny how that pattern works, no?). I thought it was a great game though.
CoD 3 was meh. I didn’t like it as much as the other titles. It tried way too hard to be cinematic and overly “interactive”, IMO.
CoD 4 was pretty good. I liked the new direction it took.
… and then the rest was history… 
Anyway, I personally like swordfish and catfish more than cod. Swordfish and catfish are more versatile in terms of how they can be cooked, and IMO cod only works well when eaten deep-fried, like haddock.