Red Dwarf is for anyone who enjoys a good laugh, and doesn't mind taking their science fiction with a grain of salt. Yet I think it's necessary to break the show up into three distinct parts.
Part One encompasses seasons one and two, which revolves primarily around the relationship of Rimmer and Lister. The first two seasons have a great low-budget appeal (most of the scenes take place on a couple of sets)and really mixes sharp wit and satire with a sense of loneliness.
Part Two is seasons three to six, and a new character, Kryten, is added to the list (this is not bad at all: Kryten gets a lot of the best lines). With the show's growing popularity and increased budget, the characters venture more and more outside their giant spaceship and explore "strange new worlds". Action and physical comedy take more and more precedence during these seasons. This is the high point of the show's run.
Part Three includes seasons seven and eight, and in all honesty, are best avoided. Several years elapsed between seasons and six and seven, and it shows. The show's creators made several mistakes in plot, story, and character, and the actors appear to be going through the motions, and much of their character traits, which made the show so great in the first place, are missing or warped in very disappointing ways.
Still, I highly recommend the first six years of this program. They're just the motley crew I'd want to be lost in space with.