Okay. Um… wow. I enjoyed the hell out of this movie. I suspect other Firefly fans will, too, and the reviews I've seen on fan sites confirm my suspicion. That said, I can't make a confident prediction about how moviegoers unfamiliar with the TV show will react. Early on, I tried to keep an outsider's stance so I could be impartial. But I quickly realized maintaining that viewpoint would just diminish my own enjoyment of the film, so I dropped it and let myself get absorbed. There's plenty for the uninitiated to like about Serenity, but my appreciation is too wrapped up in my own preconceptions to be reliable.
Instead of trying to do justice to all the things I liked about Serenity -- witty dialogue, strong characterization, libertarian themes, yada yada -- I'll focus on just one. This is sci-fi the way I like it: gritty and realistic, not clean, white, and shiny. (Perhaps not coincidentally, Serenity's characters use "shiny" as slang for anything desirable.) George Lucas originally conceived Star Wars as a space western, but I don't think he ever succeeded in creating a true frontier feel, while Whedon does. For sci-fi fans weaned on Star Trek and its ilk, Whedon's vision of the future probably seems strangely anachronistic -- why, for instance, are people still using projectile weapons when there are laser guns to be had? But this is actually a more realistic model of technology adoption. We've had central A/C for decades now, but lots of people still cool their homes with window units. Cars from the 1960s are still on the roads. Durable capital has a way of sticking around, even when it seems obsolete, because the marginal improvement in quality doesn't justify the full cost of replacement. It's no surprise that hardscrabble space smugglers would be using less-than-current technology.