Pros:

This map is simply phenomenal, I absolutely loved it.

Lots of custom content, music, models, etc.

Exploration encouraged

Beautiful world and unique settings

Pro-voice acting 

Cons:

If you're not really good at L4D2, I can see you losing alot in this campaign, as it isn't easy nor short. 

Levels can be a bit dragging played on expert/hard eight.

Conclusion:

I haven't tried the newest update of this campaign, yet.. But I've played the release and this map is truly a masterpiece. It's one of the few maps I've played over and over, and apart from the long levels, it's fairly easy. The world's crafted to a fine design; I thoroughly enjoyed the story-driven aspect of the maps/campaign. 

The does challenge you to a certain level of expertise though, as levels are long and expansive, ammo is 'sort-a'-ish scarce. There are a couple of difficult but not impossible horde events and tank encounters that might come across as stunningly hard, but I absolutely loved the challenge. 

I never found a point where I couldn't pass apart from getting lost a few times here and there. The finale was a tad too easy I thought. 

Overall, this is a brilliant creation of a campaign.