Pros:

-Model and textures couldn't be better!
-Man, these sounds!!! 
Maybe the more realistic sounds in a l4d mod! The default sounds are so annoying and disturbing but yours sir are music to my ears (literally! x)

Cons:

what is that?! O_O

Conclusion:

Another realistic mod addition! Best Chainsaw mod out there for sure!!! I'm in love with these custom sounds! Now i'm using the chainsaw more ^^