Pros:

Everything is modded
It's good for people who enjoy MLP
Fits good with other *brr* pony mods people have

Cons:

Its L4D, 18+ not 3+
Doesnt fit post apocalyptic setting of L4D

Conclusion:

Good for people who like MLP and want their gaming experience to be the same. Furthermore, a waste of gameplay for people who aren't into the show (like me) For pony lovers its a 8/10 for non-pony lovers its a 0/10

Pros:

Makes me think of TF2
Nastacha has awesome sound

Cons:

The miniguns are usually placed in a useless places
No media to show how it exactly sounds

Conclusion:

Sounds cool, but maybe you could just make it for the M60 or M1919 Browning instead of the minigun?
and please place media to show how it souns