I just finished the book a few minutes ago, and have to say that I thought it was great. It didn't feel quite as 'epic' in scope as BtRW - despite covering a much larger span of time and events- but that was fine.
I thought the pacing of the story was fine and gave us just enough focus on key happenings over the course of a five-year period to get across the scope of the war and to convey and emphasize the Enterprise crew's pivotal role in its events.
I liked what the book did with the main ENT characters, and especially got a kick out of Archer being referred to as Commodore Archer and his reaction to the rank designation.
The book's use of its wide-ranging cast of supporting characters was also excellent, and I especially liked seeing Shrank again in a more prominent capacity than in BtRW, as well ad his daughter Talla.
The book's epilogue was also great, especially the DNA reporter seeing through the deception at the end that Tucker tried to continue to perpetuate.
I really enjoyed the book (as well as its predecessor BtRW) and am giving it an Excellent rating. It was a very fitting and satisfactory conclusion to Star Trek Enterprise's story both canonically and apocryphally and is a very solid and enjoyable piece of Trek Lit.