Pros:

It's an I.E.D just like the pipebomb, this time designed with a phone. 
Lacking in good pipebomb mods, this one really adds to the variety.
HD. I think it depends on the settings.

Cons:

Fingers clips into the phone a bit. (-0.3)
I think it's a little low on the waist in third person view. 
Any animation mod you going to release? Or make a separate mod for this?

Conclusion:

It's an improved explosive device made using a phone. You don't see that much. You ALSO don't see many good pipebomb mods for L4D2, this is one of the better ones I've seen so far.