If you like westerns then yes. If not, it can be hard going in the first few episodes but in the long run it's a very good series.
Despite what everyone says, the series works best as a short-lived show, with the movie as a nice bookend finale. I can see Whedon burning the series out like Buffy had it gone to multiple seasons.
I dunno, I'm no fan of westerns, but I thought Firefly was quite good. One of the better non-Star Trek sci-fi shows out there actually. Not as good as Babylon 5, but I'd put it in the top ten.
I do agree with you that it works best as a short lived show. I've never seen Buffy, but I have seen shows burn themselves out toward the middle of their long runs, so your point is well taken.