Absolutely, Awesomely, AMAZING. I dislike Grant Morrison Batman books, but this is really, really good. The intro from Mark Waid says it all really so I think I'll just quote him:
"All Star Superman: Volume 2 completes Morrison and Quietly's celebration of the world's best loved fictional hero and it ends as skillfully and lyrically as it began....
Superman is dying. Poisoned with solar radiation by his nemesis, Lex Luthor, the man of tomorrow must finally face down his own mortality and races the clock to compress a lifetime's worth of super-achievements into what little time he has left - the Twelve Labors of Superman....
...along the way, as all men must, he takes the time to make a Last Will and Testament. The fact that, as he writes it, he bequeaths something remarkable and prescient to Lois is touching but expected; that he concludes by leaving his own secret identity, as a gift, a final chance to keep the space-time continuum aright is an idea that crackles off the page.
There is a never-ending debate among Superman aficionados as to the value of the character's uniqueness. There are some who contend, stridently, that super-dogs, and super-girlfriends, and miniature super-survivors from a bottled city diminish Superman's purity as the Last Son of Krypton. Morrison and Quietly tackle that argument head on by making the superdoppelganger such a recurring motif in All Star Superman that it masterfully underscores through contrast exactly what does make Superman unique. It's not his powers, it's not his costume, it's not his heritage. It's that, unlike his myriad counterparts, he has more faith in us than we have in ourselves, and All Star Superman is the story of how transcendently that faith elevates and redeems the human race. Everyone Superman encounters...inherit some of Superman's values just by being in contact with him.
" Take that Batman-lovers.
"Read chapter twelve closely. Notice how the men and women of Superman's world...have so clearly been fortified with Superman's courage and reverence for truth and life. And most important, watch how Superman achieves his ultimate victory - not with a swing of his invulnerable fist but with a gift of understanding. In every fight, Superman punches when he must and grapples when he has to, but at the end of every battle, he wins his best and most decisive victories when he allows his foes to see their world - our world - through his eyes....but the big moment is the perfect line of dialogue. It comes in chapter ten, when Superman, without a second's hesitation, takes time from his world-building feats to embrace and comfort a suicidal young girl. When he tells her 'You're much stronger than you think you are,' they become the most moving words we have ever read in a Superman story.
" And they gave me goosebumps.
..."they are so perfect because they reveal in one sentence, the fundamental secret of Superman and why we love him so.
Gods achieve their power by encouraging us to believe in them.
Superman achieves his power by believing in us."
Couldn't have said it better myself. So I didn't.