There are things I like about the AK, and things I like about the VZ-58. I see a few VZ-58's here in Kabul and of couse almost everyone and his goat has an AK-47. Back home I prefer my VZ, but over here in Kabul I prefer the AK... almost an unlimited source of parts and ammo.
Its funny that some people dont realize that AK will hold open on an empty mag, one of my team mates got upset that all of our do... kept grumbling that he never saw that in 8 years in Iraq as a PSD, so I guess it depends on make, mags, and a little dirt maybe.
Can you make the bolt stay open without a mag in the rifle like on the CZ? Is there a bolt release?
I am pretty sure that it is the magazines for those AK's that have the bolt hold open, not the actual rifle itself. If you look at the magazine follower, it probably has a steel "round" welded to the follower that pops up when the mag is empty holding the bolt open.
like this:

Either way, that is a sick collection of AK's you have there, I am pretty jealous.