You know, I can't really think of a "bad" Firefly episode. It gets kinda redundant to say "another good episode," I really like the first 4 episodes, with 5 being my least favorite of the bunch.
Bushwacked really carries 2 of the overall arcs of the series. We catch a big glimpse of River and the start of her abilities. This will continue to grow and be teased out for us over most of the series, culminating int he Serenity movie.
I think the Reavers are meant to only be vaguely reminiscent of the wild injun trope from old westerns. They are actually much more (or much less) than that. Yes, they appear to be mindless savages but we'll eventually see a bigger point for them.
I loved River's face during their EVA while hiding from the feds.