althought not as good as the series with Sarah Michelle Geller it is still quite good. full of comic moments and pull on the heart strings type stuff too, so good all round. The best thing is of course is that it tells the beginning of the whole deal for Buffy, something which, in my opinion, is a bit sketchy in the series so a good watch just for that. But is also quite funny, especially the vamps (weird looking with huge ears!!)
Watch it as a background to the series, and of course if you are a major fan you have to know how it all started.
Watch out for the longest death scene of a vamp ever (they don't turn to dust in the film) and the stars in small parts, see if you can get them all!