I, for one, think that Hell is so bloody awesome. it's super hard, but not so bad as to be dissuading you from continuing through sheer number of failures. you killed everything else in the game, so dropped on you is a new challenge harder than the rest of the game combined, leading up to a boss that is harder still, and so the drive to beat it is intense. when you finally do, you find that you've freed the two big enemies you see all over the game, and they're not that bad at all. everyone lives, everyone's happy, and Quote, Curly, and Balrog fly off into the sunset.
tl;dr: Hell because Give Up Already hard > Hell > Not Hard Enough, and big happy bonus ending laced with Crowning Moment of Heartwarming