If it were close to any of those shows I'd probably say Farscape. There's a healthy dose of humour, and both revolve around a rag-tag crew who've just fallen in together.
I see where you're coming from, but while I LOVED Firefly, I could never just get into Farscape.
It's a matter of opinion of course, but I feel there was a warmth to the interpersonal relationships in Firefly that was missing in Farscape, sometimes they seemed downright mean to each other on Farscape, and the whole universe never coalesced for me, there seemed to be no set of rules it played by, which was both a strength and a detriment I think.
As to the OP's question, really the only way you'll know is to watch the show, I'd never liked a Whedon show before Firefly, but I think it's one of the most important sci-fi shows in recent history. There's not much else you can compare Firefly to, because the things that are comparable in tone or setup generally fail miserably.