Get the series. It is on Netflix
I already have the series. My son bought it for me the same Christmas the Serenity movie came out on DVD. I’ve also seen the series on the Sci-Fi network and Universal HD.
After watching the series, I went back and watched the movie again and this time the movie had so much more meaning. It was a good thing I had not seen the series before I went to the theater to see the movie. If I had known the importance of the characters before hand, I would have wept like a child and embarrassed my son beyond measure.