I have Lucky Charm 7 on my looter and I drink beer before I loot containers so that I have 9 Lucky Charm, from what I've noticed, it does increase the % chance of finding extra loot. The quality of the loot is random, usually legendary though. (Pink)
It's easily the best way to find good loot far as I've found. I have no solid numbers on this though, perhaps data miners do.
