The basic premise of the series is that a space station which has been built to be essentially a futuristic version of the UN and has a mission to prevent war becomes in essence a nexus for the coordination in the greatest war in a thousand years. The series lasts five seasons and (like the Mahabharata) includes a prolonged prologue and a prolonged epilogue. The "extended miniseries" format requires the audience to watch small stories suited to a single sitting but also connected and interwoven in a complex way, following a greater arc. Some have compared it to a soap opera but that's not a very apt description.
The acting does not start off as well as it might, although some characters do very very well from the beginning. As the characters settle into their roles, things become much, much better.
The series is full of mythological elements, and includes great commentaries on religious faith and sacrifice, as well as heroism, as much as these are generally lacking from sci-fi series generally. Each race has their own sets of religions: the Narn follow a system of prophets which reminds me of Islam, while the Minbari follow a religion that reminds me of modern Hinduism, and the Centauri follow a sort of henotheistic paganism based seemingly on Roman models.
In any event, the series leaves one to think about many of these things. Yet in the final analysis what makes a mark is the heroism that leads to undying fame on the part of several of the characters. In this regard it strikes me much more as an Indo-European epic, than it does a modern tale despite the setting.
Most people I have shared the series with have greatly enjoyed it. A few have not. YMMV. However, I believe that the word "great" hardly begins to cover this series. It's something that is quite different from anything else I have seen in scope and approach. Love it or hate it, it's worth watching.
Creator J. Michael Straczynski's ambitious and complex futuristic space opera charts five years in the lives of those aboard the five-mile-long space station of the title, where personal drama plays out against a tense political backdrop of looming war between bitter enemies the Centauri and the Narn.