I wouldn't say that I'm not a fan of space westerns, as such. Alasdair's outro mentioned the Fallout games, for example, and I am a dirty, dirty Fallout whore. I love all of them, but I love (wait for it) New Vegas most of all. Further, much of the science fiction that I read as a kid (and am still reading today) was stuff from the pulp era that was essentially cowboys and indians where all the author did was change the cowboys to spacemen and the indians to aliens.
My impression of Firefly, from listening to fans of the show go on_at length_ about it, is that it isn't really a space western. It's more of a space spaghetti western with a generous layer of Joss Whedon snark slathered on top. First, I do love me some spaghetti westerns and I've watched about a million of them. There are Roku channels with scads of them, did you know that? But only the Italians know how to do them right. American attempts to capture that sensibility, even with Clint Eastwood personally involved, just don't get it right. Secondly, and I know that in many places this would get me burned at the stake as a heretic, I don't like Whedon's dialog. I know it's supposed to be all cool and snarky. it comes off to me as all smart alecky and irritating, instead. (Cue Crassus) This is, once again, simply a matter of taste, not appetite. In this case, I don't happen to like the oysters, though the snails are good. If you enjoy both, well and good.