My RPG group and I just played our first session of it last night. Notably, it's the first non-D&D rpg I've ever played.
As for character creation, I liked how that went, as I was able to quickly come up with a concept and implement it without much trouble. It was very simple to create a character with the skills I wanted (Gunfighting/Negotiating skills), and extremely fun to play.
For those who don't know and are curious, Serenity uses d3-d12, and has no roll modifiers to speak of, it just involves rolling multiple dice (i.e. to hit, I roll my agility stat, which I spent 8 points in to have a d8, and my skill with whatever weapon, which I have d10 in shotgun, rifle, and pistol, and I can deal damage equal to how much I beat the targets defense roll (comprised of agility and armor, I believe) plus however much I roll for weapon damage.
The book itself is very nicely done, with everything well organized and easy to find. My only problem with the book is that it tries to condense the setting into a few pages and succeeds; there just isn't much there. Still, this can always be overcome by a creative GM.
Overall, I had a blast making my character and playing this game, and I haven't seen Serenity (yet) or even all of Firefly. I recommend it to fans of the series, but not to anyone who's just looking for another sci-fi rpg. It's a wonerful and well thought up setting, but too light to support the imagination of anyone who hasn't seen the show/movie.