I discovered the show in a desperate search for more sci-fi that was similar to Firefly. I am confident that readers of this blog are aware of what Firefly/Serenity is. Perhaps they are even Browncoats-
Browncoat - a term applied to fans of the short-lived television series Firefly. The name is based on a nickname for the Independent Faction from the series.To me Firefly is a younger cousin of Blake. It had a much shorter life, too- Firefly running for 14 episodes and a film compared to Blake which had 52 episodes. And yet, it got it's own roleplaying game. I still wonder if Firefly's creator, Joss Whedon, is/was a Traveller rpg player since the setting is so similar to the game's and mostly Wash even calls the crew "travelers" which seemed kind of out of place unless you think of the game as that reference.
There was a very limited release Blake's 7 RPG once upon a time. Available to fan club members only or something like that. Some reviews say it used a system similar to Chaosium's BRP. While it would be really cool to find a copy of it, I don't think it's really necessary because the elements of the setting are generalized enough that almost any generic RPG system could easily recreate what we see on screen. Traveller seems like a natural fit for Blake's 7 and Firefly. Other systems, like D6, True20, or BRP, the powers might have to be dialed down a bit as they definitely never took front stage in either show.
There are other shows that fit the descriptions of each, like Farscape, but Farscape has a lot more fantasy elements than either Firefly or Blake. My own opinion is the anime series Cowboy Bebop fits better than Farscape (I believe Cowboy Bebop and Firefly could almost seamlessly be set in the very same universe).
Another thing Firefly and Blake's 7 have in common is there are often rumors or news of each returning. Nathan stirred up the Browncoat community with his stated desire to bring Firefly back. And there have been reports on and off again of a Blake's 7 revival similar to the success that Doctor Who has been experiencing. I believe Blake's 7 is not coming back as of this writing, but kind of looks possible.
So, if you're a Browncoat looking for more quality sci-fi to fill that void left by FOX when Firefly was killed, find yourself some Blake's 7. It's pretty good stuff.
Find out more about Blake's 7 at the official fan club website - HORIZON