I just got back from seeing HP 4. It was fantastique....sad, but fantastic. I think non book readers will be bloody confused; it moves so quickly and has to leave so much of the detail out. But for the rest of us, it does a splendid job of activating our memories of the book and is therefore quite emotionaly engaging.

It's a bit like how a personal happy snap of someone or something is just another boring photo if it's unfamiliar. But if you know the person, place, or event depicted - particularly if you were there when it was taken - then it represents more than just what it depicts. This Harry Potter movie is like that.