The Griff reads like someone took a novel and illustrated random pages. There's a marked lack of continuity between panels. It feels poorly researched; little thought was put into the alien biologies or the military hardware or the logistics of interstate travel while under constant assault by giant flying alien carnivores.
Moore's trademark humor appears in brilliant bursts, and I laughed out loud a few times. Rosero's art occasionally looks wonderful but his (her?) characters are inconsistent, facial features are different from one panel to the next. The characters themselves are a lot of fun: schwag whore, soldier/makeup artist(!), video game-designer babe.
Moore wrote in his preface that this story was just too visual to be a text novel and would fare better as a movie or graphic novel. He was wrong.