What loot should I be grabbing from mercenary missions?

I've been doing mercenary missions recently, and I don't really know which loot is best to pick up for extra profit. I've just been grabbing the guns I like using and nothing else really, but I know that people bring those portable storage containers into the bunkers and loot almost everything, but I don't want to sit there for 15 minutes looting everything if it doesn't get me a decent bit of money.

What do you guys take from the bunkers? Do you even take anything?