Blue force's heavy body armor(call "carrier" in the game) has cover both front and back of the body, thus should offer more protection than the Red force counterpart.
But after several trials, I found they have practically no difference.
It's take 4 shots from a 9mm pistol to kill a fully armed rifleman, both side.

test info:
weapon: 9mm pistol
range: 5m
aim: center mass(body)
result:4 shots(Blue)/4 shots(Red)