Pros:

Excellent Lighting Effects
Powerful new shading effects
Fits with L4D2
Don't kill weak CPU's and GPU's
Increase L4D2 atmosphere and graphics level considerably

Cons:

None whatsoever

Conclusion:

Best Cinematic Mod with little to no cost on performance. Definitely recommended more then other graphics mods which will drain your performance (ENB and SweetFX)

Pros:

Awesome
The swings actually effect the gibs

Cons:

Only 5 weps?
A slight delay on down swings

Conclusion:

This would be prefect if you added more animations to the other weapons

Pros:

Amazing Level Design
Right Amount of guns
AI can surprisingly take their own
Huge Maps
Freakin Awesome challenges
Great Voice Acting

Cons:

Ellis is british?
I swear if I see another Jockey...

Conclusion:

Best mappack I've ever played or seen