Almost four stars but not really, though I will bump it up to four. It was definitely better than Swallow's "Nightfall" - it ran more smoothly, there was a very logical process in going from point A to point B, the characters were rather true to themselves and the idea itself was awesome (horror and scifi in one). Also, I love stories that take place in Atlantis because the show itself took precious little time to explore the city which was a shame. And then there was the Apollo and it was nice to see its crew in action, again something that we didn't really see on the show.
But there were two things that quite didn't click for me:
a) All the technical jargon. Sometimes dumbing it down serves the story better. Some parts were a bit hard to follow for someone without a background in physics.
b) Sam Carter was without any doubt the main character of the whole story. John and Rodney were reduced to supporting characters, Teyla had one big scene and Ronon was background material (even the author's original characters had bigger parts). I missed the team terribly, the interaction between the main four: John, Rodney, Teyla and Ronon.
To sum it up, a very good, action-filled tie-in. But I miss the female touch of the previous books, the focus on the relationships between the characters.