I really do like this mod, but it has a lot of issues. I'll write here what I found, hoping that the modder will read this message.
Oh, the list refers to MP only, as I haven't tried out this mod in zombies yet.

1 - The UZI can't be selected in MP: the first time you load the mod you can select it in both default and custom classes, but when you start the first match the UZI gets replaced by the MP5. Also, if you did any classes with the MP5, this won't show up in the game.
When you end the match and return to the MP menu, you can see in the SMG category that the UZI has disappeared. So... No UZI to play :'(

2 - The sounds are too loud: like really, shooting an AK-47 in this mod is a bit like shooting multiple nuke bombs with a rocket launchers, it literally blows up your ears. Same goes with MP40 and many other weapons.

3 - The SCAR-H's fire rate is too damn high! When and where in the hell did it shoot this fast!?

4 - Attachments don't work: that's a pity, I was really hoping they worked :(

5 - Some guns still don't support camos: M1911 is one of them, but there are more (can't remember which ones at the moment)

That's all I guess, if I notice I left out some things I'll add them in the comments.