Well, I'm a non-book reader for HP and I pretty-much got everything. Came back a few hours ago from my *movie day* watching HP7 and I'm serious; LA is right. And as far as story goes, it's not just the story that's incredibly intriguing, but the acting... good Lord, the acting is excellent, especially when compared to the other six films. Emma Watson stole the show, I think, in terms of dramatic pose.
As far as the transition from book-to-film goes, I may have not read the novels, but my sister has. She knows them quite well, especially considering how she read them all very recently this year. She says Deathly Hallows was spot-on with what Rowling wrote. Practically nothing is left out, and anything that might not make total sense in this film is surely to be revealed in part 2. If anything, the only real unexplained part in part 1 was the significance of Grindelwald, besides knowing that he stole the elder wand. That's about it. I'm sure you'll find it satisfying, HNM.