Pros:

-Daring Do's color scheme fits very well
-Cutie marks are subtle and fit in very well
-The Ponyville Armory on the side is a nice subtle addition

Cons:

-No custom sounds but this is easily solved by using a sound mod

Conclusion:

An excellent pistol reskin that appeals to bronies such as myself. Keep up the good work! ^_^

Pros:

Does exactly what it says, adds Derpy to the mailbox
Blends in nicely with the environment so it's not distracting
Derpy's frequently show as a mailpony so  placing her here makes sense

Cons:

Image is kind of grainy if you look at it up close but who has time to do that while fighting zombies?

Conclusion:

A simple mod for fans of the show who want to add a little more pony to their L4D2 experience.