So the human remnants are headed to the center of the galaxy. Unfortunately, even though I was a science journalist way back when, the concepts that Benford wants to get across - the high gravity environment, the differing passage of time, the energy beings that seem to have forgotten who they are yet still talk, all of which are related to the arcane world of modern physics, i.e. quantum gravity, etc. - were for the first time completely incomprehensible to me. Even worse, with some exceptions like Toby or the resurrected Shibo, Benford seems far more interested in his ideas than he is in characters or even a coherent plot. I could not get myself to care about the characters, to suspend my disbelief and get into the story as if it were possible, or even to doubt that the outcome would be stupidly predictable. I did not want to try very hard to understand the physics.
This is extremely unfortunate, because the first 4 books really held my attention as some of the best current scifi I had yet read, idea novels that had great characters. In a way, it is like Benford is trying to milk a good thing when the gland is already empty. He is pushing the grand concept novel to a logical extension, and it stretches things so far that it breaks.
Not recommended. He wrote this too quickly, didn't care to formulate a better plot, and essentially turned me off to his writing, which I regret.