In my guild, in our raids, we use loot council, in which only i am in (the council) Master Loot is always switched to me.
I ask members to roll for an item, then i ask people to link the item they have in the same slot as the loot. I compare and judge by World-PvP attendances, not fucking up a lot in the raid, and overall impression as a player, and quite more judge by how much big is the upgrade one will get. Then i judge who deserves the item the most and choose.
If the one i chose has not won the roll, i ask the one with the highest roll to pass it down to that person, if he refuses (which really almost never happens since ppl happy to see their guildmates winning loot) i may ask to compensate with gold in return if i insist, if he refuses again he wins the loot. (Dont remember the last time i reached this point with a guildie).
If a pugger wins roll on some loot i really want to see a guildie get, i may offer gold (etc recently hunter won zulian cloak, i paid him 25g so he passes loot on guildie)
Often guildies decide to pass loot to other guildies, when i see such incident i make sure respect is gained for that action, might even offer gold as gift. Who gets the loot is often discussed, guildies often let me judge for loot, the rolls just point me at who should i head first.
About a dozen of ZG runs as guild and still no loot drama, so far so good
