I've ran both and seems to me the ZZZ holds up better with less stretch- ZZZ has a stronger tensile / shear strentgh I believe as well--- strongest of the EK chain line--- hit up a board sponsor if you need one- they will do you good on the pricing and service
ZZZ is a little stronger but not much, then again it is a little more expensive. Both chains are WAY stronger than stock chains. ZVX2 is available in colors ZZZ does not. Both use the zero stretch technology so there shouldn't be more adjustment difference between the two. I have been using the ZVX2 for a couple years, and will continue to.