Here's what I didn't like:
- Connecting Soong to Exo III sort of cheapens Soong's achievement in my book. Now, I realize this is sort of silly, because of course it makes sense that Soong's genius would not have developed in a vacuum. However it hit a sore point with me at the time because I felt like I could see a pattern of the franchise undermining its own legends by over-explaining them through continuity acrobatics. The major, most grating example of this for me is the Temporal Cold War on Enterprise during which Archer gets tipped off to the later creation of the Federation, thus emotionally cheapening the entire premise of the franchise of humanity managing to better itself under its own power. It's also just a big small universe syndrome thing ...
- I have a thing for good locked room mysteries and Coil kind of tickles that in the beginning, but then unceremoniously sweeps it under the rug ...
- Parts of it just felt a bit shaky and not very fleshed out, in particular some of the actiony bits were quite rough (e.g. that hand-to-hand combat scene with Riker) and the hideout towards the end.
Pretty much covers it. I'd add that the interesting locked room mystery is thrown away cheaply and disappointingly, the book reads like a loosely thrown together continuity exercise and was a real let down.