Pros:

-excellent additional areas
-alot of new areas are completely new, not just slightly altered existing ones
-exploration is very rewarding
-quite challenging

Cons:

-almost no good guns, really you only find smgs and chrome shotguns
-the church bell has FAR FAR too much health
-shooting pillars and climbing over the barbed wire roof is silly
-special infected often appear as 3/4 of the same type at the same time
-train and tunnel kill more than they save, especially when playing with bots

Conclusion:

an excellent campaign map, with plenty of imaginative and interesting new areas. it would be my preferred remake of the original death toll campaign were it not for the lack of good guns/ammo and some flaws with crescendo events, such as taking too long to destroy something or getting incapacitated by an annoying feature.
overall i would recommend, but i think it needs a bit more work.