I never got to make a post about Firefly, so I guess I'll just smoosh the series and movie post into one.
Firefly was a short-lived sci fi show on Fox that took place in a wild-wild-west type futuristic setting, a lot like Cowboy Bebop with a bit more "old western" feel to it. It followed the diverse crew of a smuggling ship named Serenity as they tried to eke out a living and not kill each other. The major plot point that persisted in each episode involved the ship's doctor and his seventeen year old sister who had been experimented on by the obligatory big bad government entity, The Alliance, and their efforts to avoid recapture. The captain of the ship, or "boat" as they call them, is a veteran from the losing side of the Unification War which The Alliance started, and won, in order to unify all the planets in the system under one governmental body. And there's the pitch.
Other than seeing mentions on Slashdot and the like when the show was actually still on, I never paid it much attention. It wasn't until after it got cancelled after its eleventh episode and its vocal fan base started an uproar on the Internet that I took notice and got curious.
So after snagging the DVDs of the series off NetFlix and getting hooked by its originality and cleverness, I got retroactively pissed about the cancellation of a show I could have given two shits about when it was actually running. It doesn't help that they cancelled the damn thing right when it seemed things were going to get interesting.
With that being said, I went into the theater not wanting to see a "movie-ized" version of the show, but a two and a half hour long episode, and that's exactaly what I got. Due to this I can't really comment on how you'd like the movie if you never saw the show, but if you liked the show you'll be happier than a pig in shit.
Of course there's a lot more of what you'd call "closure" in the movie than in any episode, but that was to be expected and I don't think it was to any level that would damage any revival of the television series. On the other hand I doubt it will set the world on fire with its box office take so any future series is doubtful and I'm fine with that. That would add a bit more to its similarity with Cowboy Bebop: it had its brief run and closed shop up pretty tightly at the end giving the fans enough wiggle room to pine for some sort of follow up after it's all said and done.