Snaps
Snaps have a tight grip but can snap open if the stress on the connection gets to strong. - But better an open Snap instead of a hole ripped in your vest.
- the usual Boba Chestplates dont have to deal with teh amount of stress or flexibility like other armors.
Magnets:
Never have seen a good Magnet Seal can flip of and also good rare earth magnets are annoying when they grab every single magnetic thing and stick it to your flakvest ^^
Velcro: Easy to sew on Flakvest but you need a good or alopt glue for the part on the plates if you dont want the velcro stripps ripped off.