NOTICE: I don’t count Bus Depot, Town and Farm as separate maps since they aren’t canon, they are all in one map (story-wise).
Me personally? I love Nuketown Zombies, because it’s the last map where Samantha is the zombies announcer, and the whole point of the map is the easter egg reference on the events of Moon (from BO1) and it only has four classic perks. I also can’t help but feel that the size of TranZit doesn’t work for me (It’s still a good map) and sometimes smaller maps are way more immersive. That’s just my opinion.
So Nuketown Zombies wins it for me.