In my opinion, this is the best one out of the trilogy. Nothing mind breaking, but knowing what the books have been doing in recent times, even something that's not a complete disaster is worth noting. Won't be too spoilery.
The deadliness of the Alien is represented well here, the early deaths were vivid. The science experiments were nice, the new development from the lifecycle is an example how to introduce new things with the Alien. Liked the different types and the gestation change. Great references from the RPG.
Loved the ending action sequences! Very fun to read, well described. But the synths were to robotic again...
The main marine connection to the Resistance comic made me roll my eyes. That was not needed. Also, a few maybe not inconsistencies, but unclarified things that harbor back to the RPG. The main problem is that the trilogy didn't amount to anything. It was supposed to be set during the Colony Wars and we haven't seen almost any of that. The Border Bombers aren't properly cleared up as to whom is responsible, especially with that ending... Nothing's really clear, or makes sense as to motive or possible alternative suspects (other than the ones the book spelled out for us). It doesn't seems as mysterious as it seems more clumsily done.
The writer is pretty respectful with the Alien itself, but the plot has loose ends and the characters do feel a bit flat sometimes. I wouldn't be upset to see them again. Nothing really made me irritated in the book like things did in the last two, just felt a bit more average. Still, IMO better than the last few I read (better than Prototype and Inferno's Fall by a small margin, a lot better than Colony War, Rift War and Infiltrator).