Richard Benjamin was very good as the idealistic galactic sanitation worker, Adam Quark, and Tim Thomerson, often seen as a heavy, was hilarious as "Gene/Jean", the male-female crewperson. Patricia and Cyb Barnstable carried on ably as the brainless blonds, Bettys I and II, arguing the question of which was the clone and which was the original. Bobby Porter as "Andy the Android", Conrad Janis as "Otto Palindrome", and Alan Caillou as "The Head" were very good in their roles. My favorite was Richard Kelton as "Ficus Panderata", the highly evolved plant man, a Vegaton. I would swear that his was the character in mind when they created the character of Data for Star Trek:TNG.
This show was witty, bright, and more than a bit sarcastic and cheesy. I have read in another comment that a winter storm that knocked out power in the Midwest was responsible for the demise of "Quark", but in my never-to-be-humble opinion, it was that the majority of viewers simply couldn't deal with the fact that it was so different from anything else on TV at that time.
Considering some of the stuff out on DVD today, I don't see why Rhino can't put "Quark" out for us, "Quark"'s small, loyal fan following.