Having finished it, I can say I really liked it. Still not a TOS/5YM lover after reading this though.
In any case, the biggest thing about this book is what I realized after having finished it. It's NOT a whodunnit novel, as in, someone mysterious is destroying unknown colonies, we need to find out who!! It's a novel about characters, about people. I was quite amazed at the end how much I cared about the Sulu storyline, how I was intrigued about this side of Kirk we haven't seen much off.
David's style of writing was what kept me in the novel the most though. In one chapter, there is some dialogue between Kirk and McCoy, but we follow it from Sulu's POV, which was very interesting.
All in all, I will say that this is not David's best novel, for me personally. But having said that, I would recommend this novel to anyone looking for something that's not galaxy-changing, not about the big events that change the fate of the universe. This is a novel for people who want to read how the effects of seemingly small events can change people, have a lasting effect on them, and make them look at things in a new way. I liked it. I really, really did.