I've been hearing great things about the movie. I haven't seen Firefly but from what I've heard, Serenity is an entity in itself and doesn't require prior knowledge about the TV series to enjoy the movie.

Also, Joss Whedon is a genius. I'm not even kidding about this, the man is the master of Sci-fi and I will watch anything he puts out. Even if it's a story about how boogers took over the world.

I don't know any other person who can bring so much wit and humanity to any story like Whedon can. Not even J.J. Abrams can hold a torch to this guy. I'm a Whedon fangirl, I'm not ashamed to admit it.