I went to a pre-screening tonight, and I loved it! Some of the alterations really bugged me, but its such a breathe of fresh air from the darkness of the past 3 movies! Of course there were the dramatic parts, but there was a wonderful, uplifting tone to most of it that really makes you think there could be hope for them. All in all I thought it was a great addition to the movies, especially since OOTP wasn't one of my favorites.
Also, it really sets it up for you that the final films will go out with a huge bang.
"He found something that he wanted, had always wanted and always would want— not to be admired, as he had feared; not to be loved, as he had made himself believe; but to be necessary to people, to be indispensable."
-F. Scott Fitzgerald's This Side of Paradise