I think its a waste of time. I can imagine finishing hell difficulty and getting lvl 60 with that. Or even doing act 1 in inferno. But the items you get and the character you make are for that game mode only and can be lost just like that. Can't bother playing that many hours without being able to carry it over to the regular mode heroes. even gold is separate. I understand the appeal of the mode, but they could have tried doing it differently. Its the same difficulty as regular with just the catch of permanent death.