It's very good so far (admittedly, only five episodes isn't a huge sample to base an opinion on) - very close to the original Blood Gulch Chronicles but with newer, more refined versions of the characters (and with Wash, obviously). The humour's back to the older character-based jokes, but it's fresh material and very funny. The storyline also shows promise, though not much has been revealed yet.

(On a personal note, EWW H4 MARK VI, but that doesn't affect the show's quality.)