I had high hopes for White Wolf's newest addition to the World of Darkness. Sadly, I was quite disappointed in the actual game.
First of all, it doesn't seem to fit in at all with the existing World of Darkness. Unlike the other books it doesn't even try to give stats for the other creatures, and worse, I can't remember a single reference to them at all. To make things worse, it doesn't mention the Inquisition, which would be the natural enemy of the demons. It makes up a new Church organization instead. For pity's sake, even Werewolf mentioned Inquisitors, mostly just to mention that Inquisitors usually don't hunt werewolves. When you're a demon, you're definitely gonna attract the Inquisition's attention.
The second problem was the actual demons. None of the clans really appealed to me at all, which was quite an unpleasant shock. The whole Demon book seemed to be coming from so far out in left field that I couldn't associate it with anything I'd heard of previously, which cut into that whole imagination-firing thing the other books had going for them.
The plot, as far as I could tell from the trippy and rather uninspired intro story, is that demons have just recently come to Earth, apparently driving off the Wraiths in doing so (?). Some of them, the guys you play, are trying to reachieve their angelic status, while most of them just rage around killing stuff.
The "change" that you knew was coming isn't a normal human coming to the realization that he's a monster, it's a monster coming to the realization that he's a normal human. What I mean by this is the the demons have all possessed mortals, and must now learn to live with that. But don't despair, in true World of Darkness fashion you've got plenty of cool new abilities to sling around.
Maybe some day when they release new editions of the old games like Vampire and Werewolf, they'll mention the Demons and get them truly initiated into the World of Darkness. But for now, they're basically just new-kid-on-the-block party-crashers trying to assert themselves in an existing world.