So I saw it last night. I thought it was OK. You can watch the movie without knowing the series, but I think it would help out much more to know the series. You can pick up the character quirks fairly easily, but the big picture to me seemed like a "so what" since I didn't know the series. It's long/slow it parts. The characters have their own places, but seem the usual fodder. Also, it seems at times to play like a long episode instead of a movie, not only story wise but some shot set ups seemed this way too.
I was yawning and wondering when it'll wrap up. It was only a 7pm show. On the forums, fanboys are hoping for sequels or for the show to be picked up again. I may watch the dvd's to see if I can get into it over time. For now the firefly needs to stop blinking.