I read John Shirley's other Hellblazer book Subterranean as well as the Constantine movie novelization and loved both of them, so I was excited to read this one as well.
Honestly, it's a bit disappointing compared to the other two books. The story somewhat meanders and it's tough to follow in some spots. It also dealt a lot with war and the politics of war which didn't interest me. The book is well written and Constantine is awesome as usual, but the story itself just didn't interest me as much as the other two Shirley Hellblazer books.
However, if you like Constantine, then, by all means, read this book.