I´m a fan of sci fi generally. B 5 is one of my favourites. I don´t think DS 9 was a copy. Indeed both came around the same time. Both have their own flavour.
I just purchased the first two seasons on DVD and watch them. It is hard to decide which is the best series.
At best I like B 5, DS9, SG1. Then Andromeda, TNG, TOS, Voyager and Enterprise (latter has potential). Also I liked Galactica, but only the first seasons. When they changed the story I didn´t like it. It was a pity they did.
Also a good small series was the German Raumpatrouille Orion. It had a good story but the effects were not so good. But in which serie you have a flat iron to do something. Or other stuff. Well it was the early 60s when they filmed it...

The UFO series I don´t like that much only some of the costumes were VERY sexy

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Star Wars is another outstanding series although rather movies. The first 2 parts wre not so good, but Jar Jar is not such a bad character I hate.
Oh B5 is very influenced by Tolkien. Lorien, Vorlons= Valars, Minbari= Elves, Sheridan and Delenn as Beren and Luthien, Ranger. Perhaps it is so good because of this!
Adler