Pros:

-All of them seem to fit their class fine except for the zombie pigman.

-The witch surprised me. Not what I was expecting at all (in a good way).

Cons:

-The zombie pigman doesn't match his role here, but there's nothing else I can think of, so I won't deduct any points.

-There are no FPS arms.

-Ghast throws dirt blocks.

Conclusion:

This is a great mod. But I would suggest that you just remove the  FPS arms from the boomer, the hunter, and the tank if possible. I would also suggest that you change the ghast a little bit. You should make the ghast throw fireballs, rather then dirt blocks.

Over all I highly recommend this mod to anyone who likes minecraft.

Pros:

-IT'S A CREEPER!
-It is very well animated
-It has custom sounds

Cons:

-It has the basic boomer FPS arms

Conclusion:

It's a very well done mod. It would be cool if you could change the boomers FPS arms or remove them entirely. 
I highly recommend this mod.