Just got back from seeing Harry Potter with daughter and two neighborhood friends. They loved it, and the audience of youngsters cheered at several points.
I thought that the treatment was adequate, but not as imaginative as it could have been. I especially felt that the film was trying so hard to be faithful to the book's plot points that it sort of hopped along, like a stone skimming on water, and that there weren't enough moments to get to know the characters. For example, if I hadn't read the book, the moment when the kids begin to suspect Snape would have seemed to come out of nowhere. (This is no small thing, because the emotional thrust of what little narrative thread there is in the book depends a great deal on Harry's growing sense that Snape is out to get him; it could have been developed better without sacrificing other elements.)
There were also some production miscues, here and there, that perhaps only a film professional would have noticed. Still, they smacked of sloppiness. The closing scene seemed like it had been shot rather perfunctorily; either that or they used an odd film stock.
The cast, though, was terrific, and they really gave it all they had. I especially liked Emma Watson's performance (the girl who plays Hermione). Her withering, disdainful gazes were great. Rupert Grint (Ron) was adorable, too.
I would be interested in hearing the reaction of someone who never read a HP book.