Beginning premise: I read only the first four books in the series, but had seen all of the previous movies. However, my memory of Part I of this last installment was not fresh enough for me to feel other than I was being tossed into the middle of a plot without a rudder as this film began. (Were I making a Part II and starting it mid-plot, I would have had a brief preface skimming quickly through the high points of the plot of Part I.) Thus I felt a bit disoriented at the beginning of the film, which wasn't helped much by the less than splendid enunciation of the young actors as they tossed out bits of dialogue. But the plotting is actually rather simple-minded, so I locked on pretty quickly.
That said, this is a reasonably exciting installment, the special effects work well, Ralph Fiennes as Lord Voldemort is pitiable, the young actors who play the main characters have grown well in their parts, the British stage veterans who play the Hogwarts faculty stalwarts are splendid as usual, and the little postlude is a welcome addition. I can't imagine anybody who has seen the previous movies will hesitate, but I would not recommend this film for Potter novices, if any there still be. It will seem pointless, since the main point of this film is taking very familiar characters with whom we've grown over a decade, and follow them to the climax of their tale. Having at least a vague recollection of the back-story is necessary for this to have much meaning.