Finally saw the movie, two weeks after release. I gotta say, even though I didn't watch the show, I really liked this movie. I loved how they put some funny lines to add a bit of comedy to the plot.
Oh, and is it just me, or is everyone in the Firefly universe insanely tough to kill? I'm not going to ruin it, but damn, they can take some serious beatings.
My only real issue with the movie, which can probably be expected, is that it starts off as really confusing for people who haven't seen the show. I didn't know why they were on that mission. Also, I got the feeling that the Shepherd Book guy had some significance, but it wasn't really explained.
Now I have to watch the show to understand it.
EDIT: Also, I loved the part with the operative guy and the swarm of Reaver ships. Seeing him flustered was pretty funny.