I liked the other HP movies, but this one was a disappointment.
The special effects were good, but not good enough to mask the minimal plot/story development. The flow was choppy, the logic minimal, and it seems that if only if you read the book would it make any sense.
It seems that the main plot and storyline is character love interest development, with the 'half blood prince' and 'Harry Potter history' taking a significant backseat.