Pros:

+ Makes every playthrough much more diverse and less repetitive.
+ The addition of Uncommon Infected gives a small challenge and change in combat tactics.
+ Supplies dropped from Fallen Survivors give you a welcome boost, especially for those total BS moments.

Cons:

- Gore and body damage effects won't work with the zombies imported from L4D1, but there's probably not much that can be done about that.

Conclusion:

A must-have mod for me, much thanks.