Is it a good read? Yes. Much of the book is truly historical and yet written in a way that makes it pleasant to read, something not always true of such narratives.
The authors also raise the issue of various groups which would be pleased at Patton's death, very pleased in the case of the Russians. They hint at conspiracy, but never draw any conclusions. The authors end up reluctantly implying the car accident that led to his death was probably the result of drunk driving by the joy-riding truck driver who hit his limo.
My bottom line: it is a fun book but not a great book. A good read but only so-so as history.