Just been watching this..
SPOILERS
..and must admit that I really like this instalment. For one thing I think they nailed the effects here, they are superb and the cinematography is also of a very high standard.
Half Blood Prince is a more mature Potter film compared to the five films previously. It also has the emotion at the end which really adds to the story.
When Dumbledore falls to his death at the end this is a real gutter punch for the audience but this act sets up the final two films beautifully. It’s just a shame though because, imho the final two films were abysmal! They really were bad. Shame.