Series I strongly recommend this show.
Far too few shows are written with the care and preparation of Babylon 5. Each of the main characters has a five-year arc that plays like a novel. No single protagonist is painted as absolutely good, but by the show's conclusion few characters are left morally ambiguous. One thing I will note is that the show is an extended but not hostile deconstruction of the messianic archetype; all but two or three of the main characters have some aspect of this archetype, becoming saviors to their homeworld or returning from the dead at crucial moments. Biblical imagery is used sparingly to this effect. If any of this offends you, this show may not be for you. The special effects are love-them-or-hate-them stuff, no question, but the show has a dark nineties aesthetic to it that I like. The acting could be called, in places, uneven, but I think it shows a realism that more trained acting doesn't always convey.
It's epic, and it's my favorite show. You may not like it, but if dark sci-fi's your kind of thing, it's awesome.
Series Will cramp your butt at times, but worth it
B5, a Tolkien setting in space with political intrigue. Half of the show is a fly by the seat of your pants, good vs. evil epic. The mundane side of station life, however, is handled with verisimilitude. We got Blue, Red, Brown sectors. We got Walther PPKs that shoot heated plasma (awesome). We have a huge metropolitan station which will take five years to explore fully.
Comparisons with Trek are inevitable, though as I just described, B5 is whole other kettle of fish:
Earth is not some hippie utopia; it was forced to adopt the worst of all utopias, the one-world government, out of grim necessity. Religion has followed us into space, and while the Mosiac religions are looking a bit neutered these days, the station is still full of vicars and rabbis doing their thing. B5's species, like Star Trek, are various placeholders for... the human condition. The decadent Centauri are ripe for collapse; the Narn want to join the Big Boy's club (refuting allegations of being 'backward') but are so hobbled by a century of exploitation that they slide right back into their fundamentalist ways; the pragmatic Minbari strive to improve themselves while stepping on any meddlesome races that get in their way, etc. The more things don't change, the more they stay the same, that's what I always say.
Refreshingly, unlike Trek, they can't easily be summed up as black hats or proud warrior races. When one of the aggressors get their comeuppance (and there will be many reversals of fortune), it's always tinged with regret.
Like I said, though, the setting may be hard sci-fi, but the plot is about as hard as jello pudding. This works well for the antagonist aliens, a Lovecraftian race of scheming beetles. Plot resolutions, however, are about as subtle as J.K. Rowling. Giant weaponized planets, angels, zombies, psychics, wizards: This show has it all. I found this to be the biggest hurdle, because it's so at odds with a carefully-crafted world, and it made me take long breaks from the series at times. The long-winded philosophizing sure doesn't help. Hey, Straczynski! It's called a visual medium!
I'm no good at wrapping up reviews, so: I like B5. It did what it set out to do: craft a tight story within a set five-year limit with unique, likeable characters.
Series Casual viewer's impressions
It's hard to review a series in a few paragraphs, let alone Babylon 5, so I'll dissect the parts that pleased me.
Acting: The acting on this show is consistently excellent, though the scripts and direction sometimes let the side down. Women are usually the strong point of any sci-fi show, and this is no exception. Besides Furlan, Tallman is probably the best actress, and her Lyta quietly steals the show in s.4 Ivanova has such an expressive face! Talia is great and I missed her once she left.
As for the men, the Captains are likable, if a little wet. G'Kar and Londo are obviously the heavy-hitters, but Marcus is a laugh riot throughout. Garibaldi is a little flaky but he has some great, darker moments and a fun little "private investigator" arc running in Year Four.
I can take or leave Franklin and Delenn. (Sorry)
Themes: Space punk, LOTR in space, Dali Lama gobbledegook, a stinging indictment of the media and the cowardice of people who trade freedom for security...yes, you can guess which one I enjoyed the most!
The depiction of a corrupt Earth is more relevant than ever and the AMAZING takedown of the news media still gives me chills today. How did they get away with that?
Production: The production value is very high and still looks good, with crisp sets and a judicious use of shaky cam. Apart from the goofy sci-fi lettering on every sign, newspaper and placard, it doesn't seem dated. The CGI is the worst aspect of the show, bar-none. Had it aired a few years later, it might look as good as Farscape or SG-1.
Story: The show suffers from a preponderance of scripts by Stracinzski. He's a great ideas man but doesn't have an ear for dialogue, and the myth arc is a little flabby; the show truly shines when it focuses on the minutiae of everyday life on B5/Mars. I did enjoy the bits with Lorien (credit to Wayne Alexander) and the First Ones, and the Centauri Prime scenes.
It's easy to see why B5 has such a cult following. In spite of the 90's cheese factor, high fantasy trappings, the romantic treacle, and the somewhat stagey dialogue (everyone talks like Klingons), it's a show which takes risks and rewards you for paying attention.