New zombies. Its much harder to get to high rounds, and the implementation of buildables just makes it better. Tranzit is kind of bad though, the lava and denizens ruin everything, but Die Rise is the best zombies map ive ever played on, considering that fact that i never bought any dlc for blops 1. Kino was way too easy, getting to round 28 solo was a breeze, and "FIVE" was way too hard because of the small amount of space you had and the pentagon thief. I think the next dlc zombies map will be fantastic. I heard it will be called "Bridging the Gap" on Der Kammer.
I would say old black ops so far, only because I don't really like Tranzit. Though I love the grief mode they implemented. I could definitely see the new zombies being more fun though with different maps. I just hope they don't go the Tranzit route for newer maps.
Old maps > new maps because I hate the fog and lava, the fog prevents me from enjoying the scenery, I feel ascension is a great map or was, because it had camping spots and allowed for running and gunning, it was a fair size. I feel the same way about five and Der reise. Now we have a map that thankfully has no fog or lava, but as if zombies were not enough of a issue in those tight hallways we now have jumps and drops which a little accident will mean instant death.
The only map I genuinely did not like on Bo was moon, the rest didn't bug me, granted George is a pain, on bo2 there is not a map I genuinely like yet, nuke town is to small and tight otherwise it is the best of the junk we have available.
I have done the Easter egg already on die rise but every time I jump or drop off a ledge I hold my breath just a little.