So very, very 80s. I mostly liked it (except for the multiple times Bailey paraphrased André's actual writings really really closely), but I doubt the André in the book bears much resemblance personality-wise to the real man. It took me a while think of what he did remind me of, because I kept thinking it was a sort of washed-out version of Gore Vidal's Aaron Burr, and then I realized it was actually Charlie Schuyler, the other (and frankly less interesting) narrator in Burr.
Bailey also did something that's rapidly becoming a minor pet peeve of mine when it comes to sympathetic characterizations of André (I think JJ Feild claimed this too in an interview) - André loving America and seeing himself as quasi-American or wanting to stay in America, and I just think there's no evidence for this. I mean, he certainly thought parts of it were pretty, and I don't think he hated it, but I also think it's more likely that he was never that attached to America and his home was always England. I think the meme of André the American has more to do with the fact that he's ours now, bitches, because America seems to have stayed fascinated with him for far longer than Great Britain did than anything the real John André actually felt.