The reward is enormous though, so we recommend you do it.
This bonus is not cut like experience from monster kills when you are past Clvl 75, so this quest is always a huge boost, but if you can save it (borrow a portal to the Worldstone Keep) until you are Clvl 80 or 85 it's even more valuable. Or you can go straight to the Arreat Summit and click on the altar.
