Pros:

Improvement from the god awful original.
The endings where nice touches (The Suicide one surprised me)
The characters have eyes now
The story seems a bit more L4D style, and less like so Hollywood B movie.
Map 3 was decent.

And the biggest pro is it is actually playable in Coop

Cons:

Bland level design!
Needs more posters/graffiti around the campaign.
The Bunker was Cut and Paste right from Cold Stream
Some of the Voice actors were really immersion breaking (Like the one that talks to you the radio, and makes you search for files)
Survival Mode is broken
Able to get out of the map in a few spots
Was able to see L4D1 survivors in map 1, before we are suppose to meet them
Clipping issues
Also the Tank appearing on the finale randomly, is REALLY cheap, it needs to have a warning.

Conclusion:

A lot better than the previous entry, still feel it could use some touching up. Add some Bioshock-style propaganda, I feel it would fit well for your campaign and could make it a lot less bland. But still it needs some work to be perfect. You are getting there, just fix the maps itself and make it more alive then the campaign will be perfect.

Pros:

Haha This is funny I laughed when I saw this
Best mod out there for bill and it fits him.
Detail is great.

Cons:

None

Conclusion:

Great mod for bill everyone should have it.