I will go ahead and say that I am an unashamed Harry Potter fan.  I have enjoyed each movie more and more as the story and characters have aged and become darker and darker.  I stopped reading the books after the third so, aside from hearing spoilers, the movies are completely new to me at this point.

QUALITY:
Decent.  The picture is nearly flawless except for a few random scenes that get grainy with no apparent explanation.

BONUS FEATURES:
Featurettes, Q&A with cast and crew, deleted scenes, sneak peak at the Harry Potter theme park in Orlando.

The bonus features are actually pretty entertaining.  The only disappointment is that the "sneak peak" at the 'The Wizarding World of Harry Potter' really doesn't show anything of the park itself but it does give you insight into what it will be like.  The movie itself is a little bit of a downer, it's an obvious bridge into the finale and feels like a filler.  With that comes a bit of a feeling that something was missed in between this movie and the last and it feels as though you are shoved right in the middle of a story that you have to attempt to fill in the blanks yourself.  I'm still lookig forward to the final films but this one was a small hiccup in an otherwise fantastic series of films.