I've seen Firefly mentioned on here a few times before and a few years ago I found a cheap Serenity DVD, which I enjoyed, so it didn't take much for me to go "ooooh, cheap firefly box set... mine!" (also found X files series 1 and a few films).
Watched the first episode last night. Very impressed. Having watched Serenity spoilt some of the Simon/River plotline, but there were enough other plots going on to compensate for this.
I haven't seen a huge amount of Buffy, so may be making a sweeping generalisation from what I have seen, but the characters in it in the episodes I have seen have seemed quite shallow. Whereas, in this first episode of Firefly, Whedon seems to develop much deeper characters. From the brief introduction of the first episode it's not clear what to make of them all or how the open battle scenes will fit into the over story of the captain.
I'm not a bit fan of westerns either, but it's interesting to see their influence coming through. The whole first episode screams "western set in space" at you.
*hmmm_tea suspects this was money well spent*