I use the "hard" plates. Realism, and also find it helps distribute heavy loads on the rigs (kinda like a solid frame in a backpack). I can carry a lot more weight comfortably than with a soft assault vest, for example.
The hollowness of the plates is somewhat annoying. I'm looking at suitable materials to fill them and make the fully solid. (resin, fiberglass, something... still looking)
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