I have rank one on my engineer and it seems to make a difference. If I am repairing a vehicle that explodes I tend to be left with between 60% health and 20% shields. Without it I am either dead or below 50% health when this happens. Not a scientific analysis, but I think so.
it can save your life from grenades and lightnings/MBTs that try to flank an infantry position, it is something worth having on at least 1 loadout. in general though, for long term cert points most people tend to go nanoweave or grenade bandolier i would say spend 1 cert point in it, and if you are camping/going to be in a decent position for a while, use it because it can save your life from nades and tank blasts.
