OK, I saw this last night. I have seen all the movies and read none of the books, although I intend to now, before the 5th Potter movie comes out. As a casual Potter movie watcher rather than a seasoned fan of the books, I can confirm that much of the deeper plot points were lost on me, and I sometimes have a hard time keeping up with who is who, but that doesn't stop me enjoying the movie, so I guess these films are perfect in that they satisfy the fans and the casual viewer. As for the effects...Fantastic. I actually used to work for Framestore, who done a lot of the CGI for this movie, and I had the script and storyboards for this fourth film before the third was evn in theatres, and I was mighty, mighty impressed by what I saw last night. I don't know what it was, but even though I was looking at dragons and ghosts and flying horses, it looked somehow believable, and it dicked all over the effects in Star Wars 3. The moment when I most thought to myself 'shit, these effects rock' was when the dragon was chasing Harry and trying to get to him on the rooftop, knocking off tiles and breaking bricks.