I recently sat down to watch this movie again (have no idea how many times I have seen it by now!). While the movie and the TV series have very little in common, both are enjoyable for different reasons.
The movie (which came before the series) is entertaining, funny, and---if you keep it separate in your mind from the show---a good story (written by Joss Whedon). The story isn't as good as other material written by Joss Whedon...and if you do compare it to the show, there is a lot that is different between the movie and the beginning of the series---but, those differences are easily overlooked by any fan.
The Buffy movie is funny, decently acted (not high caliber quality acting, to be sure), and decently produced.
This movie also has quite a cast of actors, including Kristy Swanson, Luke Perry, Paul Reubens, Rutger Hauer, David Arquette, Hilary Swank, and Donald Sutherland.
7/10