When Michael Gambon replaced Harris, I liked him better. He was more animated, more emotional, more interesting. But then I hadn't read much. Now that I've read the 6, I am forced to agree. He's not a good Dumbledore. Rowling stresses over and over how calm and tranquil and almost unearthly Dumbledore is; Gambon doesn't get any of that.
The way he screamed at Harry after Harry's name came out of the Goblet was absolutely ridiculous. It is totally out of character. I can't believe the director allowed it.
Anyone notice that they had Parvati and Padma BOTH in Gryffindor? Padma is supposed to be in Ravenclaw.
I think the thing he is most lacking is the kindness that Richard Harris had shining from his eyes. His Dumbledore looked the characters in the eyes, and there was a spark of warmth that is so lacking in Gambon.
I miss Richard Harris so!