On a related note, I 5-box and gathering quests are the bane of my existence...

...but...

...because I have different classes with different class quests etc some of them get more exp and some get less. I find the gathering quests handy to sync up experience again. So whenever I have a gathering quest I will loot with my lowest experience characters first. This way I only hand in the quest for one or two of my characters but I keep my exp bars more or less synced. Exceptions are certain quest chains where everyone has to get the drops or where there is a juicy reward.

For instance, in Outlands my Pally is eyeing up the shield reward from the Bonechewer Blood gathering quest. I killed loads of those Bonechewers and only 2 characters have all the required drops. The shield is a 500 armor upgrade over my current shield though but the Pally is already a bubble or two of exp ahead. Conundrum.