HP6 is a much better title than Harry Potter and the Half Blood Prince to be honest because while the Half Blood Prince does play a minor part in the storyline, it is not as major a role as in the book.
Now, of course, this is understandable as a book the size of HP and the Half Blood Prince can never be boiled down to 2 and a half hours without losing some major plot lines and the plot lines that were chosen are crucial to the completion of the series, the missing story of the Half Blood Prince was also, in my opinion, crucial to how this story ends.
Perhaps WB should have considered splitting both books 6 and 7 into 4 movies rather than just 7 into 2.
Definitely a movie to see if you are a fan or even if you are new to the Star Trek franchise. This movie sets up an entirely new world of possibilities while paying homage to the story origin. A must see for the space action/adventure/opera fan.