Well, I enjoyed this. I strongly suspect that even more than the other films, you might struggle with this if you've not read the books. However, it really brought the action of the book to life, and part 2 next summer seems a long way away.
Whilst the principal actors (Daniel Radcliffe, Emma Watson and Rupert Grint) may not be the best, I feel (along with many other people, I have little doubt) that I have grown with them - they embody the characters they portray. The review in "The Times" was rather sniffy, particularly about Grint. However, they are more than sufficiently competent to allow me to suspend my disbelief - which should be the objective in a film.
A couple of really striking moments: the point right at the beginning where Hermione casts an "Obliviate" spell on her own parents - throughout, I felt Watson did a thoroughly good job of conveying the emotion of a young person comprehending the weight of what was happening to a greater extent, in some ways, than the boys; the way in which Hermione (again!) narrates the story of the Deathly Hallows, with a shadow-style animation; and, for good measure, the sequence with Harry and Ron on his return, and the horcrux.
There are plenty of shock moments - startling even when you know that they are coming - and even (considering the darkness of the story) a fair number of laughs.
Rowling Incorporated have done a very good job of bringing the books to life over the last 10 years or so, and whilst I am really looking forward to the final part, I will also be sorry to see the end of the Harry Potter era.