I'll now review both the third and fourth Harry Potter movies (Prisoner of Azkaban and the Globet of Fire, respectively) because they are highly contrasting.
The third movie is now directed by a new director (Cuarón), and both the story, art direction and movie direction are excellent. The plot introduces many characters to the series and is more complex than the two previous movies, and yet the movie effortlessly present these intermingled with some action scenes. The production values, including the special effects, are excellent, and the budget doesn't seem to be wasted: special effects that are important to the plot are well made, and otherwise they get out of the way of good story telling. Also, the actors seem to start being better and more comfortable, which help given that character development is important in this plot. Of the first three movies, this is easily the best, and maybe one of the best movies of the whole series.
In stark contrast, the third movie, directed by yet another director (Mike Newell) is an uncomfortable mess. The whole premise of the story (the competition for the globet of fire) arose in me a strong feeling of mental dissonance: Why host a dangerous competition for 17-year olds or older in a high school filled with kids? What was the point of the prize again? Why did they use caricatures of French and Russian exchange student so over-the-top that they are almost insulting? Why is the scoring system for those 3 competitions so flexible?
Oh, and I'm skipping how the other elements in the story, from the "world cup" pastiche to the lengthy ball event, and of course the whole Voldemort thing seem to be shoehorned in the story in the most awkward way possible. Now with more locations than in the previous movies, they still ended up using blue-screen stages, adding an odd feeling of claustrophobia in open spaces. So, for the fourth movie, both the story, special effects and direction sucked.