They actually are a bit longer than modern shows. An hour has been getting shorter over the years as more commercials creep in. That's why so many series have 10-second intros, if any, rather than the full 90 seconds or so B5 has.
Believers is about equal parts well-done and annoying, and in the same storyline no less. It's probably worth seeing but not critical to any ongoing story.
Yea, if you're used to the typical TNG or Voyager tropes, the ending is quite surprising, definitely handled much better than most Trek would handle the episode. Not the amongst the best episodes S1 of B5 has to offer, but, often times, even lower end B5 episodes are better than a lot of shows best episodes. And yea, if you don't have access to watch it, it's petty much standalone, so you won't miss anything arc-ish.
You can watch it on Amazon.com for $1.99 if you so choose
Always a good idea to check IMDB episodes, often times you can find free episodes on Hulu or by episode watch from Amazon for a small fee.
One Day I hope to be the Man my Cat thinks I am
Where are we going? And why are we in this Handbasket?