I felt that this was one of the better movies in the "Potter Series. Lavender and Ron were hillarious! I would have liked more footage between Harry and Dumbledore, however, it was well edited and made the story work to what needed to be presented on film. Also, I would have like more Quiddich, especially the finals with Ginny and Ron coming out victorious for Griffyndor. The story of the Half-blood Prince was neatly tied up when Snape revealed he was the "Prince".
Some may say that the movie was "slow" or had too much dialog, but this book/movie had to set up the 7th book/2 movies, especially the Horcruxes, which are the only focus of Harry and Hermoine in the 7th book.