Far too much time was spent on the "snogging" theme than on the all important plot elements which made the Half-Blood Prince, in my opinion, one of the most crucial part of this saga. While I understand the need for alterations in a book's plot when making a movie, I can not understand the shallow treatment given the principal themes of Rowling's story in favor of highlighting burgeoning teen relationships.
Still, it is entertaining enough (once I overlook that treatment of the story) for me to recommend it to anyone interested.