I actually just finished writing a fairly negative review of this movie. I, likewise, did not find any magic in up, especially when compared to the rest of the Pixar catalogue.
As for the opening, I thought the opening newsreel of Muntz and the meeting of Young Carl and Young Ellie was one of the worst openings I have sat through in ages. it was obnoxious and I didn't feel any connection to any of the characters, I also remember both my girlfriend and I laughing when we finally realized that one of them was a girl.
The montage of Carl and Ellie's courtship, marriage, and life, however, I thought was beautifully and minimally done. Superior work.
The rest of the movie, however, couldn't decide if it was funny or serious, plausible or fantastic, anything. The humor was cliched and poorly executed, the animation wasn't spectacular, characters and subplots came in and out of the movie every three minutes... Just not impressed.