I don't know if this question actually fits the bill for this sub-Reddit, but I have been reading the book and would love to get a feel for how it was received by the academic historical community.
So, I'm not a representative sample of the academic historical community, and I have not read the book, nor will I.
That said, some things which should be considered when evaluating the usefulness of a secondary source, like this book:
Neither of the authors are trained historians
The book is not published by an academic press
These are not fortuitous signs, and that's before we get into things like
One of the authors is a Fox News anchor
Donald Trump thought it was good
Donald Trump can't even be trusted to pick a decent toupée.
Like telkanuru, I haven't read the book either. It's lack of sources dissuaded me from checking it out of the library.
I was initially interested in the book because I have read "Washington's Spies" by Alexander Rose. While it's not a tight "thriller" and it may meander from time to time, the book is well researched and documented. I should say it's also interesting enough for it's length (somewhere in the 300 page range). It's been a few years since I picked it up, but I'd start there instead.