I personally did not like this "movie". It may have the same characters, but it's TOO fast paced and the story line is pretty horrid. I mean, you MAY like it if you've never seen the Hana Yori Dango anime series, but if you've seen it, you'll be HIGHLY disappointed in this movie. Yes, I know it's supposed to be set in a new time and theme, but they could have done a LOT better job on it -- the story line wasn't half as good as it could have been. They also should have spent more time on it instead of only giving ita pathetic half hour :/
Therefore I simply warn you: If you want to watch it, go for it, but don't expect anything and get your hopes up, except a movie that dishonors the anime.