VZ vs AK:
VZ is radically different from the AK. It's a very good quality piece according to those who have owned it whom I have spoken to. There are more youtube videos about it, Hickok45 has a decent video.
9mm in a .40 case:
.357 Sig is a .40 S&W necked down to 9mm in order to have a very high velocity round with a smaller nose cross section for better penetration. With modern ammunition the application it was intended for is filled by more capable and tailor made rounds like the 5.7x28.
Tanfoglio: Again, decent quality from what I understand. The Witness is a CZ-75 clone which is a proven design if you like a hammer fired SA/DA handgun.
Caracal: Been around but just recently made an appearance on Rob Pincus' youtube page if you want a good review of the Caracal F.