B5, no contest. Farscape got interesting, but B5 was a better show overall and had a better first season. Neither first season is great though.
Gotta disagree. I actually gave up on B5 early on, but was persuaded to give it a second chance when friends I trusted started raving about Season Three, and, yes, there was some epic stuff in the middle seasons, once the plot finally got underway.
Farscape, on the other hand, got off to a stronger, livelier start, with plenty of colorful, exotic characters and situations.
Both shows are good, but Farscape had the edge when it came to humor and excitement and adventure.