This one was pretty good compared to most of the other movies. The Goblet of Fire, The Order of the Phoenix and the Half Blood Prince truly sucked. The special effects and such keep getting better and better, however the older the movie the better he is IMO. I still find the first one the best, even though the quality compared to the 7th movie is bleach.
You can never expect that they add everything from a book into a movie, so that they removed things like their preparation to invade the ministry is logical and to be expected. I would have removed that piece too as it isn't important. In fact it's not like they removed it, they just didn't mention but it's pretty much implied that they did prepare it. In the movie they just jumped from one scene to another, though they didn't give any indication as how much time had passed. So you can assume a certain amount of time passed. It's a trick often used in movies in this kind of situations. They did it in LotR too.
Compared to the previous movies this one was pretty decent, still they didn't really brought the feeling from the book to life. One of the greatest things of the HP books is that small, seemingly insignificant details suddenly become incredibly important in one of the other books. The problem is that most of those details weren't even mentioned in the previous movies and suddenly they absolutely need it the current movie but looses then all its charm when they need to find another way to bring it up. For example Gregorovitch: he was briefly mentioned in some small scene as the one who made Krum's wand in the 4th book, that was a scene that didn't make it into the movie, but is important in the 7th book. In the book Harry remembered the name, but in the movie he just sees Voldemort going after Gregorovitch.
If you read the books you automatically start combining the info from the books in the movie, sometimes I can't even recall whether something was in the movie or not. Though if you haven't read the books that can get really confusing. When I saw the 4th movie, I hadn't read the 4th book yet and I didn't like it because that movie didn't made any sense at all.
But what I truly find a shame is that during the course of the 7th book Harry truly starts to understand how Voldemort's thoughts work, but in this movie they haven't shown any indication of that. It's something incredibly important to the essence of all the books, but now that's just ignored and in the 2nd part it's possible that's just going to pop up.
The animation of the Story of the Three Brothers was cool though.
