One of the issues with post-singularity, post-humanity SF novels is that you can quickly lose any sense of connection with the characters; the world becomes so foreign that you stop caring who lives or dies.
Though I stopped caring about the characters in the book, kudos to Doctorow for creating a world bizarre enough to hold my interest until the end (just barely).
I flirted with that sense several times during this novel, though ultimately, I'd suggest it was a well-written, reasonable book that others would probably find interesting.