Pros:

-Firing sounds are top-shelf
-Nifty reload & firing animations
-Magazine is neat

Cons:

-Model physics
-Walking animations could be smoothed out a bit

Conclusion:

I love this gun, especially after watching The Purge: Anarchy. The only catch is, the model clips into the ground, and doesn't lie flat. Still a nice addition to L4D2, keep it up. 

(Is there an M60 somewhere, 'cause I haven't played BF3 yet :P)