Pros:

Brilliant!  Just great!
Weapons?  Oh yes...just awesome.
Includes l4d1 survivors!  Oh god yes.

Cons:

HOW DARE YOU ADD CONS TO THIS!  YOU MUST DIE!

Conclusion:

This is one of the best mods I have ever seen, mostly because HL2 is one of the best games I have ever played.  This also includes weapons from the beta, which makes this pack the best.