I just saw it last night. I think they did a pretty good job, and the pacing was fast--there were very few times I thought they should speed up a scene so they could fit more in, but the pacing was sometimes TOO fast, and I felt a lot of stuff (particularly the beginning) wound up disjointed.
Re: Richard Harris v. Michael Gambon as Dumbledore...I'm in the minority on this one. I never liked Harris's Dumbledore, because I thought if someone sneezed in his direction, he'd fall over and break his hip. Not exactly the kind of Dumbledore that could handle the battle with Voldemort at the end of Order of the Phoenix.
I like Gambon inasmuch as he comes across as a powerful force to be reckoned with--I just wish he had a bit more of Dumbledore's whimsy.
Umbridge was a great casting choice.
I THOUGHT that was Helena Bonham-Carter. I wanted to make Marla Singer jokes every time she came on screen.