The more I think about it the more I don't like this series. But at the point where I was reading this book, I still had hope. (it ends in a cliffhanger). Tension attempts to be created by the characters constantly trying to get somewhere and talking to themselves or each other about the minutiae of every thing they do, when they should be able to figure out what the reader probably figures out pretty fast. The conversations, therefore, are mostly people talking over each other or stopping in the middle of their sentences and it makes for an atmosphere of constant fluster, thereby making the plot feel very much like sitting in stop and start traffic. The future itself is deliberately not fleshed out, I am guessing to make it feel ordinary for the characters and not to infodump (and maybe to not raise questions it can't answer), but more of a grounding would have made it more interesting, like... are there German historians researching the Holocaust? Or is research only confined to the good guys?
I do like learning about World War II. I think the concept of the book is cool and it works well enough that I read it and am reading the 2nd one.