This is a 2/5 in terms of a recommendation, but I would personally rate 3/5 because I enjoy reading Dan Simmons' books. At the pace the duology was keeping there needed to be a third book to properly flesh out some of the storylines. I still think it's worth reading if you made it through the first book, but you'll have to use your imagination if you want a proper and complete ending.
There are a number of storylines that are finished satisfactorily. The following characters and stories feel solid: Achilles (by far and away the most complete), Harman, Ada, and Daemon (despite the lack of a proper finale with Caliban).
The moravecs just seem to save the day everywhere they go. Truely a missed opportunity to not have had some showdown along with some select humans and moravecs fighting Setebos to the finish. Perhaps they could have thrown in some post-humans, brought back Nightenhelser and Patroclus to the mix... but no, they just kind of fade away.
The Setebos, Prospero, Cycorax, and Odysseus storylines either end abruptly or not at all. This is a shame because the first two are the underlying main antagonist and protaganist of the plot. There is no major finale, no final battle, no incredible confrontation. Cycorax feels haphazardly introduced and then simply vanishes, fulfilling nothing more than a minor obstacle. The Odysseus ending feels like it came out of nowhere and then he just vanishes as well. Sorry Helen. Likewise, Helen in this book feels like nothing more than a forgotten sidekick with no character development whatsoever.
Hockenberry, while playing a significant role in the book, comes across more like a "Random Adventures" story whose only real contribution was to QT a few people here and there. The post-human Gods just end up fading away in the story, fighting the Titans for the forseeable future. I guess it didn't matter in the end anyway how much they were QTing everywhere, despite the fact that the was the entire impetus for the moravecs to enter the fray. This book just ends so many plotlines abruptly or not at all it's disgusting.
There is no finale with Daemon and Caliban despite a good hundred pages of the book building it up. Ariel just kind of came and went not doing much more than simply being a taxi for the plotline. Moira likewise was there not doing much more than something of a narrative dump. There was a ton of potential for these two characters to offer something deeper than a plot contrivance. Oh well.
What this series needed was one more book. There was so much potential in situations that all come to an abrupt halt. The weak plotlines pale in comparison to the better ones. Those plotlines that are finished are incredible to read and espouse the imaginative prowess of the author. Those plotlines that are not finished are disappointing or just plain absent. Overall, perhaps the biggest mix bag of a book I've ever read.