Imo its important to keep looting rules as even as possible and leave no room for scamming especially when playing with PUGs. Personal loot system is one really good option. Money is easy to share equally between all group members and that wont be a problem at all. Personal loot system can be easily keep in balance with scaling drop rates. If an item e.g. has 60% drop rate, it will decrease to 20% each in party of three people. That way mobs will averagely drop the same amount items or resources. Of course looting purely with RNG is another option and works fine too. It might lead to situations where someone gets more than others, but in long run this will become close to even/average. We have to remember, that within guilds it does not usually matter who gets the loot and people can more easily discuss who needs the loot most and trades can be easily made.