If I say everything there is to say about this set, I'll end up with a review. I haven't played using it yet, but I desperately want to.
If you are a 3e fan undaunted by high level play, it's a stunning boxed set. Even if you aren't in to 3e or prefer lower levels, there is a lot of fluff and background material there you can plug in to.
It's 50% setting, 50% adventure. Lots of sites are statted out that you don't necessarily have to face. And interestingly enough, if the players don't play their cards right, they can get on the bad side of the Efreeti, which is not a good thing.
This is an interesting roleplaying dynamic. At the levels you have to be to play this (12th-20th), the players may be used to have their PCs be absolutely bad-ass, above any sort of law. All of a sudden, the players have to watch their backs, as they will be in a city with very not-nice laws and the power to enforce them.
There are 3 books (+ a map booklet). The first is the setting book, detailing the city and the surrounding region. There are some encounter areas, but most of the ones that are "dungeon" type areas are in the second book.
The second book is a mini-campaign of sorts, that sets the PC about finding the fate of a prophet, drawn from real legends. It's epic, and includes many old school references, including the Codex of Infinite Planes. Assuming the players stay on task, they'll make their way through a variety of exotic locations, including the so-called "Pagoda of Devils", a pyramid devoted to Set, and more.
The final book is mostly opposition--NPC stat blocks and new creatures. The book also has a variety of cool encounter ideas.
The city itself is as fantastic as the reputation suggests. Sure, it's a planar metropolis where you can access anything (for a price). But you may find things are not a given here. To get drinking water, you must entreat priests who require you to sacrifice blood for the privledge, and to even get into the city, you must wait in a miles-long line, the "highway of the damned."
Tired, maybe more tomorrow.