I enjoyed Babylon 5 back when I watched it a few years ago. I bought all of the seasons and movies, and watched it straight through and plan to do so again. But I really enjoy Farscape a lot more.
I thought Farscape was a lot more fun. B5 is basically a traditional sci-fi story, it is very well done, but IMO there is a lot more originality in Farscape. I like the characters better in Farscape, and thanks to the absolutely amazing work done by Jim Henson's Creature Shop (IMO Farscape was one of the best things they ever did) it has a lot more interesting aliens. I know a lot of people make fun of the fact that it's puppets in space, but that was one of my elements of the series. But I'm also a huge life long fan of The Jim Henson Company, so I could be a little biased.