The opening sequence was wonderfully gloomy, the three preparing for dark times in different ways. I loved how that was delivered.

The whole mood of the film was so bleak and dark, I really liked that, because that's what it was supposed to be like. Sure, the camping was slow and felt like it went on forever, but that was the point. And so beautifully filmed.

I liked how the three were actually terrorists. From the ministry's POV, they were the bad guys and that had a very special feel to it. Of course that wouldn't have worked with the poor, innocent students at Hogwarts in the former films, but it was such a major point for this film, it made it stand out even more.

The humor wasn't used as cheaply anymore as in the former films, but as a way to inhale, get some rest and a smile on someone's face before the return to dire times.

The animation of Hermione telling the story of the three brothers? Lovely. What a great idea.

The dancing scene was really awkward, but I think that worked. The three kids finally became real characters, something the 6 films before this one did not manage to pull off. Hell, I was even impressed with Radcliff's acting, and he was so bad for the first two or three films. They all finally had chemistry together and you actually cared. In the books so many bad things happened to Potter, you always cheered for him. In the films so far, not so much.
The one consistent aspect of the film series is that they cast excellent people for the adults. Ifans, Nighy, David O'Hara as the guy Potter impersonates. Wonderful.

I was always surprised how easily the fans of the books let the former films off the hook, now they finally have a film that's doing justice to its source material. So far I was always like "sure, looks good, we'll see.", had a decent time at the movies, left and never thought about it anymore. It's a whole different movie experience this time. I am really impressed and actually really looking forward to the final film. They could redeem the whole experience with the two Deathly Hallows parts, but for now, like Paul said, this film actually shows what the others were lacking.