I finished this last night and have mixed views on the book.
I found the AIs to be well developed for the most part, the Null and everything relating to that was interesting and provided something different than normal, overall it was one of the intriguing alien species I have read about in Trek for quite a while.
That said, I agree with what is said above, everyone seemed to be acting slightly hostile to everyone else, not just to the outside aliens, but towards each other. It was like someone had turned up the obnoxiousness dial by one or so on every character, and I have to say I didnt care for that aspect.
Judith Sisko wrote:
but I think having Titan become an actual character to develop would have held more potential.
I thought of this possibility, too, but:
A. it's too reminiscent of "Andromeda"
There are multiple things I would love to see incorporated into Trek from Andromeda, and sentient ships and their avatars is one of them.