FIREFLY was an acquired taste. I came to it a few years late, so I binge watched the series on DVD, when SERENITY came out. While the plots were a bit mild, the characters were really colorful. I fell in love with most of them, by the end. Nathan Fillion was very good at going to dark places, but still remaining the good guy. Summer Glau became a favorite, especially in SERENITY. Add to that, her cyborg turn in THE SARAH CONNOR CHRONICLES, which made me gaga over her.
I'll be interested to see what the reboot is like. I'm not a huge Whedon fan, so I'm game for changes, especially if there is more adventure to it. I think the characters from the original are established enough that the new filmmakers realized the fan ire they will get, if they don't have enough depth.