I finished TBTS yesterday and wanted to let it sit for a day before I commented. (MAJOR SPOILERS AHEAD)
First of all, I loved the continuation of Trip's storyline. However, the rest of the book fell flat for me. And that's painful to say for me considering how much I LOVED the previous ENT relaunch novels and Martin (and Mangels') work in the past on other titles. To me, we spent far too much time with Admiral Valdore and with T'Pau and not enough with our core characters. Perhaps since (I am assuming) this book was rushed from Book 2 of 3 to 2 of 2, there was a lot left out. It seems most of the events on Enterprise happened "off camera" and we would only catch up with them every few months. Reed, Phlox, and Mayweather were all but forgotten. (Mayweather's reunion with Archer could have been very dramatic and heartwarming in such a hollow and depressing story) Hoshi gets a bit to do, but even though she begins a relationship with Major what's-his-name, we never SEE it. We get some foreshadowing in decon, a casual reference from T'Pol, and then they're married 25 years later. Bing bang done. The same with Archer's rise to the presidency, T'Pol and Trip's relationship, and Trip's eventual rescue from Romulan space. I feel like a good 300 pages were cut from what ended up to be another botched hatchet job of a finale. The crew of Enterprise deserved better. As this is most likely the last outing for this crew (unless we have some "Lost Years" books later on to fill in the gaps), then once again the crew received their Swan Song with the focus being on other characters. (As with the disasterous These Are the Voyages... being a Riker holodeck episode.)
I find it hard to blame Mister Martin as it was most likely the powers that be that ordered the end of ENT in print format. But with the destruction of the DS9 novel line scattering the characters to all corners of the quadrant (Rough Beasts of Empire was the only flawed entry in the absolutely EPIC Typhon Pact series) and now ENT, there doesn't seem to be a lot to offer the passionate Trek reader. The focus seems to be shifting to TNG and Titan books (which, granted, have been amazing to date!!) and TOS books that don't do much in terms of storytelling (The Children of Kings was the only book I have ever started and then put down because I was bored). With the exception of Unspoken Truth and Cast No Shadow, there doesn't seem to be much in the way of continuity of epic storytelling. So, all in all, a sad day for the continuation of the Star Trek print franchise. IMHO.