The strengths of the film come from the series; the setting is brilliant; authoritarian government, frontier life with a combination of technologies from the 19th century to spaceships and lasers, vicious implacable enemies, sinister government agents. What more could you want?
Overall I prefer the series to the movie, I think the movie suffered from trying to compress an introduction to the fairly complex world and character interactions as well as a story into the two hours available. A lot of the script and character interaction came across as being heavy-handed and abrupt.