Divinity II: The Dragon Knight Saga (DKS) is a rather old-school RPG at heart.
First things first, despite the improvements since the release of Ego Draconis, DKS is not a great looking game. Some of the environments look quite nice, but the character models are pretty terrible, especially facially, and the way your hero moves makes it very difficult to really immerse yourself in the game. Case in point; jump off a 200ft cliff, he (or she) will get into the falling animation and then... nothing. They stay locked in that single frame until they hit the floor. Oh, and hitting the floor doesn't hurt one bit apparently, regardless of the size of the fall. There's no tumble, then pick yourself up, the land on both feet and carry on. It's just weird, and I find it very odd that no one mentioned such a thing when they were reworking the game. The frame rate is a bit choppy in places too, especially when it gets busy.
For the most part though, gameplay is pretty solid. It's a massive, massive game, and while I doubt many will need the claimed 100 hours to go through it, I don't doubt that you could easily put that and more into exploring the world entirely. It's not an easy game either, the regular 'normal' difficulty providing ample challenge for the most part. In many ways, comparisons with Oblivion and Fable seem appropriate, having the former's huge open world and the latter's black/grey morality infused throughout. Your choices in the game really are significant as well, much more so than in most titles that try similar things, and you'll have many life or death decisions to make.
That said, it does have problems. Your Hero is mute, making it hard to really feel anything for you in-world avatar, and most of the characters, even the big bad, are underwritten, as though the game expects you to like / hate key characters just because. Bioware do this sort of thing so much better.
So, it's a good game. Yes, undoubtedly. However, it's still not as polished as perhaps it could have been, there are still bug and it still crashes occasionally (usually whilst saving, which is very, very annoying) and it's definitely not as good as the likes of Oblivion or Dragon Age: Origins. Fable... well, Fable's much more charming, but much shorter too.
Ah yes, the Dragon. Almost forgot. No, you don't get your Dragon Powers until a good way in, probably fifteen hours or so and even then, they're a little underwhelming. Still, it's a nice gimmick.
The score then? I'd like to give it three and a half stars, because there's loads to do, and it's clearly had a lot of work put into it, but the slight sense of scrappiness to it still pervades, and the reasonably frequent glitches do take some of the shine off.
So, three stars it is. Good, but not great, and those hankering after a really good RPG with dragons would be best checking out Dragon Age, those after the best RPG on the 360 should be looking at either Oblivion or Mass Effect 2.