The only bone I have to pick with the story is that, like Celestial Madonna, it suffers a bit from the lack of a regular artist. Alan Davis left the book after doing the first three issues in the story, and they got Kieron Dwyer (with his then-inker, current writer Rick Remender) toward the end of the run, but the result was 15 issues drawn 5 or 6 different pencillers. I'm sure they would have preferred to have one regular penciller and use the "spotlight" issues for other artists.
A friend who was collecting the comics at the time also said he felt it was too drawn out, which I suppose it might be if you had to wait 30 days between each instalment. In collections, though, it works fine.
The thing I like best about this story is that even though it is a "dark" story where the bad guy wins and innocents die (though no Avengers die, somehow) and Carol kills a man, it doesn't do it by making the characters "dark" and angry and bitter. Busiek sticks to the thing that I think makes his run such a favorite of so many people, which is that all the characters are presented as the best versions of themselves, and he tries to make them interesting without showing them at their worst. (Okay, he did show Carol at her lowest, but that was much earlier in the run, and by now she's much better.) So even with a much darker story involving a more complex and scary world, the Avengers are all still the same old goody-two-shoes heroes, and they're actually more interesting for that than if they were all fighting with each other.
As one of the last "old-school" Marvel comics published in the Quesada/Jemas era, complete with the narrative captions and thought balloons and occasional flashbacks - though not nearly as many flashbacks as in the Pérez run - this story is a wonderful transition between eras of comics, a bridge between the back-to-basics, old-school superhero comics movement of the late '90s and the darker, more militarized world of early '00s comics.
Well, I recall Busiek saying here that he and Brevoort told other writers what they planned to do and gave them the option of referencing it, but most of them decided not to. The fact that no one else was referencing it may have been one of the things that kept it from having quite as much impact at the time as it might have, but I think it actually helps the story now, since (except for the 'Nuff Said issue) it's not tied in with other Marvel comics/events and can tell its own story its own way.
Between Kang's destruction of D.C. and Cassandra Nova's murder of 16 million mutants in Genosha, there sure was a lot of casual genocide in early '00s Marvel comics, though.