This isn't a stand-alone movie, but if you have read the HP books, then I think this was an outstanding effort, less choppy than the 4th and 5th ones. The actors have all matured and seem more comfortable in their roles, even as their characters themselves transform into uncomfortable adolescents. The comedic talents of Radcliffe, Watson, and Grint are impressive. Visually, a stunning movie.
In some ways, I feel like this movie is to the series what "Empire Strikes Back" was to the Star Wars trilogy. Didn't necessary wrap up anything, but necessary to set up the rest of the series, so to some viewers unsatisfactory in it leaving you hanging.