The Scientist Gone Wordy blog author reviewed The Eagle of the Ninth today. She judged that the book was very slow to start  but she concluded:

Overall, though, I recommend the book. Be sure to stick with it if, like me, you find it slow to start because it really picks up and is a very cool story… I’m looking forward to the rest of her backlist. Rating: 4 of 5 stars.

source: here