I finished this book today, took a while - other books to read as well, Who to watch and listen to - you know how it is 
Slight spoilers for future VNA:
I thought he “borrowed” a bit too much from his own book Tragedy Day for this one, particularly the Hy-Bractors.
Rose and the Doctor felt a tad too bland compared to their onscreen personas, and Jack felt a bit wasted. It seems I am in the minority, but the inserts with Das and Jack in the 21st Century felt totally irrelevant to the story and slowed the narrative down every time they came around.
Overall I would put this one at a 3,5/5 
Only one more with the Ninth Doctor to go 
