There were lots of good things going on in For Tomorrow - I thought Azzarello really did a good job slowing down the internal moments, focusing intensely on Superman's feelings and the things that drive him to do what he does. I enjoyed the origin of the Vanishing (except the clunky part about how Clark erased the memory from his own mind ). As I've stated other times, I'm a big believer in Superman being the LAST son of Krypton and I appreciate when a writer shows the impact that the loss of his entire world has on Clark. To me, Krypton should sometimes cast this sort of shadow over Superman. It's his birthworld; his entire life was born in unthinkable tragedy. I loved to see him struggle with feelings that he had to do more, had to be able to save everyone when his father could not. I LOVE this aspect of Superman, and big points to Azzarello for really focusing on it.
I like seeing a more proactive Superman. Rucka's Superman has been tighter in story, but he still suffers from the annoying problem of always going to the JLA for advice. How many other JLA-caliber heroes go to the JLA for Batman to solve their mysteries for them? I HATE when the Superman creators do that! So I appreciated seeing Azzarello's Superman go to the JLA and say, "I'm handling this, and if you don't like how I'm doing it, I'll just ask you to trust me and to stay out of my way." Batman's reaction, "I'm glad that you're taking this personally" was good as well. I think that of all the League members, Batman (to me anyway) may not see eye to eye with Superman on methods, but he'll be the first person to trust Superman to handle the problem and handle it correctly.
There were several unfulfilling moments - the villains were not terribly memorable. Zod never really had any clear motivation, beyond a nebulous "Your father did this to me" concept which was not defined clearly. Equus was two-dimensional. The priest's plot sort of petered out. He was a very effective sounding board in the early chapters, but then he is grabbed (by, I assume, the OMAC people), turns into a big monster, and then fights Equus for eternity apparently. It was a strange and fairly pointless direction for his character's arc to take. I'm not sure that I understood why the elemental forces were attacking Superman or why the girl who controlled them convinced Wonder Woman to go after Superman. She didn't seem to have much point.
On the art-front, Jim Lee's art was good. I'm not a huge Jim Lee fan, but I must admit that he is an effective action-adventure artist. Some of his panels hit extremely hard, and Azzarello really gave him some great visual tapestries to cut loose on. Outer space, the ocean floor (pointless scene though it was), the Fortress, the Phantom Zone paradise, Metropolis, the Middle East - Lee made it all look dynamite.
Overall, despite its flaws, I enjoyed it. It could've been tighter and better (trim out the elementals and give more room to Zod and his reason for having such a powerful affect on the Phantom Zone), but I had a fun time. Perhaps the critical hating that this arc took may have also lowered my expectations as well. ;)