Does the monster of the week live on in Primeval?

I was recently watching season one of the British show Primeval and it struck me that this show is the perfect example of the ‘monster of the week’ format. The show’s entire premise revolves around capturing, stopping, or killing monsters that enter modern times through time portals. Sometimes the monsters are from long ago; at other times they are from the future. There is an underlying story of the team assembled to stop these creatures and the phenomena causing all these time portals. As with any show involving time, things get confused when events occasionally serve to change the timeline—a convenient reason to completely shake up the show, add or remove characters, or even alter the ‘world’ in which the shows exists.

Until I stumbled on this show I’d thought the ‘monster of the week’ format had become a dying breed. Some shows like Fringe masquerade as ‘monster of the week’ until they can get up and running with a longer story arc, but it seems to be the longer stories that really build a fan base. Or so I thought. Primeval is heading into its fifth season and seems to change characters often. Even traditional SciFi favorites like Star Trek and SG1 held tightly to a core group of characters to pull fans along through their very episodic formats. The beauty of episodic shows is that they are easier to pick-up mid season or to watch in a hit or miss fashion. For show creators, it is a double sided coin—viewers don’t feel compelled to watch every week but you also don’t lose viewers who might give up if they miss an episode or two.

Do you like ‘monster of the week’ shows or do you prefer longer story arcs?