Is it worth watching?
Have you somehow missed the hundreds of thousands of posts extolling the virtues of Babylon 5? I'm talking just here on Ars. I think between that and Farscape, those are the two most beloved series on this forum... Don't even say "but fire...." That's in a class all by itself.
Personally, I love SG-1. There were about 3-5 years I was basically putting on B5 or SG-1 and letting them play while I was home. And I would slip in Buffy the Vampire Slayer as well.
B5 starts out rough. The series does not have the best actors. But it also has some of the best actors. But that first season starts all kinds of threads that weave through the entire series and lays some eggs that hatch over the course of the series. It is very cool when you connect the dots and realize they made an effort to tell a cohesive story and tried to take it seriously.