id say teir 2 experts in rift are harder then the heroics in wow, lack of addons to help you out, also rift experts Crush the tank so its really important for a geared tank and good healer. there isnt much room for error in t2 experts untill you out gear them but even then it still hard. The Instance system in this game is very diffrent then wow. even at lvl 50 if i go to a lvl 17 dungeon i still need a healer if im going to kill multiple mobs and as a rogue tank i dont do much damage so i stlil need dps in there to kill the stuff. So the as a Whole i think the Rift entire instance system is harder then WoW's