My group is DK tank, boomkin, fire mage, ele shammy, and destro lock. I wanted different classes and figured I could do serious fire damage with the improved scortch buff and destro fire buffs. To be honest I haven't really looked at how well it is stacking (if at all) but the group is fun to play and has lots of utility (teleport, summoning, water, totems, replenishment and stat buffs). I don't have a dedicated healer, but that might change. So far it hasn't been an issue if the druid and shamm heal the tank at the same time.