I watched all but the last HP movie, then read the books...
... and I can say without a doubt that this was a masterpiece.
I write this, because I see that most of the criticism of this movie goes on about a few things, namely:
* The differences in character behavior
* Omitted information
This is the turning point of the series, from kiddy movies to something that can hold the interest of kids, teenagers and adults alike.
I've read on these forums that omitting the backstory of the Marauders Map is "unforgivable", but the person who wrote this undoubtably read the books first. This information is not missed.
Someone said that omitted information was an indication that the movie was "tailored" for people who had already read the books, but this isn't true. As with any book-to-movie adaption, things have to be cut out, and the best stuff to cut is the extra information. The lore, the detail. As interesting as the information is, can you imagine the info-dump in the shrieking shack translating to film? That scene was exhausting to read (not boring), imagine if you could actually hear the yelling and arguing. Excessive information is probably the big difference between the book and film universe, and it was handled perfectly.